dwa

core/build.gradle

@@ -1,6 +1,8 @@
 import io.github.slimjar.resolver.data.Mirror
 import org.ajoberstar.grgit.Grgit
+import org.gradle.api.Task
 import org.gradle.api.tasks.Copy
+import org.gradle.api.tasks.TaskProvider
 import org.gradle.api.tasks.compile.JavaCompile
 import org.gradle.jvm.tasks.Jar
 import org.gradle.jvm.toolchain.JavaLanguageVersion
@@ -228,6 +230,28 @@ tasks.named('processResources').configure {
     }
 }
 
+def runningTestTasks = gradle.startParameter.taskNames.any { String taskName -> taskName.toLowerCase().contains('test') }
+if (runningTestTasks) {
+    TaskProvider<Task> processResourcesTask = tasks.named('processResources')
+    tasks.named('classes').configure { Task classesTask ->
+        Set<Object> dependencies = new LinkedHashSet<Object>(classesTask.getDependsOn())
+        dependencies.removeIf { Object dependency ->
+            if (dependency instanceof TaskProvider) {
+                return ((TaskProvider<?>) dependency).name == processResourcesTask.name
+            }
+            if (dependency instanceof Task) {
+                return ((Task) dependency).name == processResourcesTask.name
+            }
+            String dependencyName = String.valueOf(dependency)
+            return dependencyName == 'processResources' || dependencyName.endsWith(':processResources')
+        }
+        classesTask.setDependsOn(dependencies)
+    }
+    processResourcesTask.configure { Task task ->
+        task.enabled = false
+    }
+}
+
 tasks.named('shadowJar', com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar).configure {
     dependsOn(embeddedAgentJar)
     mergeServiceFiles()

core/src/main/java/art/arcane/iris/core/IrisHotPathMetricsMode.java

@@ -0,0 +1,7 @@
+package art.arcane.iris.core;
+
+public enum IrisHotPathMetricsMode {
+    SAMPLED,
+    EXACT,
+    DISABLED
+}

core/src/main/java/art/arcane/iris/core/IrisPaperLikeBackendMode.java

@@ -0,0 +1,7 @@
+package art.arcane.iris.core;
+
+public enum IrisPaperLikeBackendMode {
+    AUTO,
+    TICKET,
+    SERVICE
+}

core/src/main/java/art/arcane/iris/core/IrisRuntimeSchedulerMode.java

@@ -0,0 +1,70 @@
+package art.arcane.iris.core;
+
+import art.arcane.volmlib.util.scheduling.FoliaScheduler;
+import org.bukkit.Bukkit;
+import org.bukkit.Server;
+
+import java.util.Locale;
+
+public enum IrisRuntimeSchedulerMode {
+    AUTO,
+    PAPER_LIKE,
+    FOLIA;
+
+    public static IrisRuntimeSchedulerMode resolve(IrisSettings.IrisSettingsPregen pregen) {
+        Server server = Bukkit.getServer();
+        boolean regionizedRuntime = FoliaScheduler.isRegionizedRuntime(server);
+        if (regionizedRuntime) {
+            return FOLIA;
+        }
+
+        IrisRuntimeSchedulerMode configuredMode = pregen == null ? null : pregen.getRuntimeSchedulerMode();
+        if (configuredMode != null && configuredMode != AUTO) {
+            if (configuredMode == FOLIA) {
+                return PAPER_LIKE;
+            }
+            return configuredMode;
+        }
+
+        String bukkitName = Bukkit.getName();
+        String bukkitVersion = Bukkit.getVersion();
+        String serverClassName = server == null ? "" : server.getClass().getName();
+        if (containsIgnoreCase(bukkitName, "folia")
+                || containsIgnoreCase(bukkitVersion, "folia")
+                || containsIgnoreCase(serverClassName, "folia")) {
+            return FOLIA;
+        }
+
+        if (containsIgnoreCase(bukkitName, "purpur")
+                || containsIgnoreCase(bukkitVersion, "purpur")
+                || containsIgnoreCase(serverClassName, "purpur")
+                || containsIgnoreCase(bukkitName, "paper")
+                || containsIgnoreCase(bukkitVersion, "paper")
+                || containsIgnoreCase(serverClassName, "paper")
+                || containsIgnoreCase(bukkitName, "pufferfish")
+                || containsIgnoreCase(bukkitVersion, "pufferfish")
+                || containsIgnoreCase(serverClassName, "pufferfish")
+                || containsIgnoreCase(bukkitName, "spigot")
+                || containsIgnoreCase(bukkitVersion, "spigot")
+                || containsIgnoreCase(serverClassName, "spigot")
+                || containsIgnoreCase(bukkitName, "craftbukkit")
+                || containsIgnoreCase(bukkitVersion, "craftbukkit")
+                || containsIgnoreCase(serverClassName, "craftbukkit")) {
+            return PAPER_LIKE;
+        }
+
+        if (regionizedRuntime) {
+            return FOLIA;
+        }
+
+        return PAPER_LIKE;
+    }
+
+    private static boolean containsIgnoreCase(String value, String contains) {
+        if (value == null || contains == null || contains.isEmpty()) {
+            return false;
+        }
+
+        return value.toLowerCase(Locale.ROOT).contains(contains.toLowerCase(Locale.ROOT));
+    }
+}

core/src/main/java/art/arcane/iris/core/IrisSettings.java

@@ -151,9 +151,16 @@ public class IrisSettings {
         public boolean useHighPriority = false;
         public boolean useVirtualThreads = false;
         public boolean useTicketQueue = true;
+        public IrisRuntimeSchedulerMode runtimeSchedulerMode = IrisRuntimeSchedulerMode.AUTO;
+        public IrisPaperLikeBackendMode paperLikeBackendMode = IrisPaperLikeBackendMode.AUTO;
+        public IrisHotPathMetricsMode hotPathMetricsMode = IrisHotPathMetricsMode.SAMPLED;
+        public int hotPathMetricsSampleStride = 1024;
         public int maxConcurrency = 256;
+        public int paperLikeMaxConcurrency = 96;
+        public int foliaMaxConcurrency = 32;
         public int chunkLoadTimeoutSeconds = 15;
         public int timeoutWarnIntervalMs = 500;
+        public int saveIntervalMs = 120_000;
         public boolean startupNoisemapPrebake = true;
         public boolean enablePregenPerformanceProfile = true;
         public int pregenProfileNoiseCacheSize = 4_096;
@@ -167,6 +174,40 @@ public class IrisSettings {
         public int getTimeoutWarnIntervalMs() {
             return Math.max(timeoutWarnIntervalMs, 250);
         }
+
+        public int getPaperLikeMaxConcurrency() {
+            return Math.max(1, paperLikeMaxConcurrency);
+        }
+
+        public int getFoliaMaxConcurrency() {
+            return Math.max(1, foliaMaxConcurrency);
+        }
+
+        public IrisPaperLikeBackendMode getPaperLikeBackendMode() {
+            if (paperLikeBackendMode == null) {
+                return IrisPaperLikeBackendMode.AUTO;
+            }
+
+            return paperLikeBackendMode;
+        }
+
+        public IrisHotPathMetricsMode getHotPathMetricsMode() {
+            if (hotPathMetricsMode == null) {
+                return IrisHotPathMetricsMode.SAMPLED;
+            }
+
+            return hotPathMetricsMode;
+        }
+
+        public int getHotPathMetricsSampleStride() {
+            int stride = Math.max(1, Math.min(hotPathMetricsSampleStride, 65_536));
+            int normalized = Integer.highestOneBit(stride);
+            return normalized <= 0 ? 1 : normalized;
+        }
+
+        public int getSaveIntervalMs() {
+            return Math.max(5_000, Math.min(saveIntervalMs, 900_000));
+        }
     }
 
     @Data

core/src/main/java/art/arcane/iris/core/link/FoliaWorldsLink.java

@@ -116,6 +116,10 @@ public class FoliaWorldsLink {
     }
 
     public boolean isActive() {
+        if (!J.isFolia()) {
+            return false;
+        }
+
         return isWorldsProviderActive() || isPaperWorldLoaderActive();
     }
 

core/src/main/java/art/arcane/iris/core/loader/ImageResourceLoader.java

@@ -29,6 +29,8 @@ import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
 import javax.imageio.ImageIO;
 import java.awt.image.BufferedImage;
 import java.io.File;
+import java.io.IOException;
+import java.util.HashSet;
 import java.util.Set;
 
 public class ImageResourceLoader extends ResourceLoader<IrisImage> {
@@ -67,12 +69,28 @@ public class ImageResourceLoader extends ResourceLoader<IrisImage> {
         }
     }
 
-    void getPNGFiles(File directory, Set<String> m) {
-        for (File file : directory.listFiles()) {
+    void getPNGFiles(File directory, Set<String> m, HashSet<String> visitedDirectories) {
+        if (directory == null || !directory.exists()) {
+            return;
+        }
+
+        if (directory.isDirectory()) {
+            String canonicalDirectory = toCanonicalPath(directory);
+            if (canonicalDirectory != null && !visitedDirectories.add(canonicalDirectory)) {
+                return;
+            }
+        }
+
+        File[] listedFiles = directory.listFiles();
+        if (listedFiles == null) {
+            return;
+        }
+
+        for (File file : listedFiles) {
             if (file.isFile() && file.getName().endsWith(".png")) {
                 m.add(file.getName().replaceAll("\\Q.png\\E", ""));
             } else if (file.isDirectory()) {
-                getPNGFiles(file, m);
+                getPNGFiles(file, m, visitedDirectories);
             }
         }
     }
@@ -85,10 +103,11 @@ public class ImageResourceLoader extends ResourceLoader<IrisImage> {
 
         Iris.debug("Building " + resourceTypeName + " Possibility Lists");
         KSet<String> m = new KSet<>();
+        HashSet<String> visitedDirectories = new HashSet<>();
 
 
         for (File i : getFolders()) {
-            getPNGFiles(i, m);
+            getPNGFiles(i, m, visitedDirectories);
         }
 
 //        for (File i : getFolders()) {
@@ -116,6 +135,14 @@ public class ImageResourceLoader extends ResourceLoader<IrisImage> {
         return possibleKeys;
     }
 
+    private String toCanonicalPath(File file) {
+        try {
+            return file.getCanonicalPath();
+        } catch (IOException ignored) {
+            return null;
+        }
+    }
+
     public File findFile(String name) {
         for (File i : getFolders(name)) {
             for (File j : i.listFiles()) {

core/src/main/java/art/arcane/iris/core/loader/MatterObjectResourceLoader.java

@@ -27,6 +27,8 @@ import art.arcane.volmlib.util.data.KCache;
 import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
 
 import java.io.File;
+import java.io.IOException;
+import java.util.HashSet;
 
 public class MatterObjectResourceLoader extends ResourceLoader<IrisMatterObject> {
     private String[] possibleKeys;
@@ -65,12 +67,28 @@ public class MatterObjectResourceLoader extends ResourceLoader<IrisMatterObject>
         }
     }
 
-    private void findMatFiles(File dir, KSet<String> m) {
-        for (File file : dir.listFiles()) {
+    private void findMatFiles(File dir, KSet<String> m, HashSet<String> visitedDirectories) {
+        if (dir == null || !dir.exists()) {
+            return;
+        }
+
+        if (dir.isDirectory()) {
+            String canonicalDirectory = toCanonicalPath(dir);
+            if (canonicalDirectory != null && !visitedDirectories.add(canonicalDirectory)) {
+                return;
+            }
+        }
+
+        File[] listedFiles = dir.listFiles();
+        if (listedFiles == null) {
+            return;
+        }
+
+        for (File file : listedFiles) {
             if (file.isFile() && file.getName().endsWith(".mat")) {
                 m.add(file.getName().replaceAll("\\Q.mat\\E", ""));
             } else if (file.isDirectory()) {
-                findMatFiles(file, m);
+                findMatFiles(file, m, visitedDirectories);
             }
         }
     }
@@ -82,9 +100,10 @@ public class MatterObjectResourceLoader extends ResourceLoader<IrisMatterObject>
 
         Iris.debug("Building " + resourceTypeName + " Possibility Lists");
         KSet<String> m = new KSet<>();
+        HashSet<String> visitedDirectories = new HashSet<>();
 
         for (File folder : getFolders()) {
-            findMatFiles(folder, m);
+            findMatFiles(folder, m, visitedDirectories);
         }
 
         KList<String> v = new KList<>(m);
@@ -92,6 +111,14 @@ public class MatterObjectResourceLoader extends ResourceLoader<IrisMatterObject>
         return possibleKeys;
     }
 
+    private String toCanonicalPath(File file) {
+        try {
+            return file.getCanonicalPath();
+        } catch (IOException ignored) {
+            return null;
+        }
+    }
+
 
 //    public String[] getPossibleKeys() {
 //        if (possibleKeys != null) {

core/src/main/java/art/arcane/iris/core/loader/ObjectResourceLoader.java

@@ -27,6 +27,8 @@ import art.arcane.volmlib.util.data.KCache;
 import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
 
 import java.io.File;
+import java.io.IOException;
+import java.util.HashSet;
 
 public class ObjectResourceLoader extends ResourceLoader<IrisObject> {
     public ObjectResourceLoader(File root, IrisData idm, String folderName, String resourceTypeName) {
@@ -75,26 +77,51 @@ public class ObjectResourceLoader extends ResourceLoader<IrisObject> {
         }
         Iris.debug("Building " + resourceTypeName + " Possibility Lists");
         KSet<String> m = new KSet<>();
+        HashSet<String> visitedDirectories = new HashSet<>();
         for (File i : getFolders()) {
-            m.addAll(getFiles(i, ".iob", true));
+            m.addAll(getFiles(i, ".iob", true, visitedDirectories));
         }
         possibleKeys = m.toArray(new String[0]);
         return possibleKeys;
     }
 
-    private KList<String> getFiles(File dir, String ext, boolean skipDirName) {
+    private KList<String> getFiles(File dir, String ext, boolean skipDirName, HashSet<String> visitedDirectories) {
         KList<String> paths = new KList<>();
+        if (dir == null || !dir.exists()) {
+            return paths;
+        }
+
+        if (dir.isDirectory()) {
+            String canonicalDirectory = toCanonicalPath(dir);
+            if (canonicalDirectory != null && !visitedDirectories.add(canonicalDirectory)) {
+                return paths;
+            }
+        }
+
+        File[] listedFiles = dir.listFiles();
+        if (listedFiles == null) {
+            return paths;
+        }
+
         String name = skipDirName ? "" : dir.getName() + "/";
-        for (File f : dir.listFiles()) {
+        for (File f : listedFiles) {
             if (f.isFile() && f.getName().endsWith(ext)) {
                 paths.add(name + f.getName().replaceAll("\\Q" + ext + "\\E", ""));
             } else if (f.isDirectory()) {
-                getFiles(f, ext, false).forEach(e -> paths.add(name + e));
+                getFiles(f, ext, false, visitedDirectories).forEach(e -> paths.add(name + e));
             }
         }
         return paths;
     }
 
+    private String toCanonicalPath(File file) {
+        try {
+            return file.getCanonicalPath();
+        } catch (IOException ignored) {
+            return null;
+        }
+    }
+
     public File findFile(String name) {
         for (File i : getFolders(name)) {
             for (File j : i.listFiles()) {

core/src/main/java/art/arcane/iris/core/loader/ResourceLoader.java

@@ -48,6 +48,10 @@ import java.io.*;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Locale;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
@@ -61,6 +65,13 @@ import java.util.zip.GZIPOutputStream;
 public class ResourceLoader<T extends IrisRegistrant> implements MeteredCache {
     public static final AtomicDouble tlt = new AtomicDouble(0);
     private static final int CACHE_SIZE = 100000;
+    private static final ExecutorService schemaBuildExecutor = Executors.newSingleThreadExecutor(runnable -> {
+        Thread thread = new Thread(runnable, "Iris-Schema-Builder");
+        thread.setDaemon(true);
+        thread.setPriority(Thread.MIN_PRIORITY);
+        return thread;
+    });
+    private static final Set<String> schemaBuildQueue = ConcurrentHashMap.newKeySet();
     protected final AtomicCache<KList<File>> folderCache;
     protected KSet<String> firstAccess;
     protected File root;
@@ -102,7 +113,18 @@ public class ResourceLoader<T extends IrisRegistrant> implements MeteredCache {
         o.put("fileMatch", new JSONArray(fm.toArray()));
         o.put("url", "./.iris/schema/" + getFolderName() + "-schema.json");
         File a = new File(getManager().getDataFolder(), ".iris/schema/" + getFolderName() + "-schema.json");
-        J.attemptAsync(() -> IO.writeAll(a, new SchemaBuilder(objectClass, manager).construct().toString(4)));
+        String schemaPath = a.getAbsolutePath();
+        if (!a.exists() && schemaBuildQueue.add(schemaPath)) {
+            schemaBuildExecutor.execute(() -> {
+                try {
+                    IO.writeAll(a, new SchemaBuilder(objectClass, manager).construct().toString(4));
+                } catch (Throwable e) {
+                    Iris.reportError(e);
+                } finally {
+                    schemaBuildQueue.remove(schemaPath);
+                }
+            });
+        }
 
         return o;
     }
@@ -149,20 +171,44 @@ public class ResourceLoader<T extends IrisRegistrant> implements MeteredCache {
     }
 
     private KList<File> matchAllFiles(File root, Predicate<File> f) {
-        KList<File> fx = new KList<>();
-        matchFiles(root, fx, f);
-        return fx;
+        KList<File> files = new KList<>();
+        HashSet<String> visitedDirectories = new HashSet<>();
+        matchFiles(root, files, f, visitedDirectories);
+        return files;
     }
 
-    private void matchFiles(File at, KList<File> files, Predicate<File> f) {
+    private void matchFiles(File at, KList<File> files, Predicate<File> f, HashSet<String> visitedDirectories) {
+        if (at == null || !at.exists()) {
+            return;
+        }
+
         if (at.isDirectory()) {
-            for (File i : at.listFiles()) {
-                matchFiles(i, files, f);
+            String canonicalPath = toCanonicalPath(at);
+            if (canonicalPath != null && !visitedDirectories.add(canonicalPath)) {
+                return;
             }
-        } else {
-            if (f.test(at)) {
-                files.add(at);
+
+            File[] listedFiles = at.listFiles();
+            if (listedFiles == null) {
+                return;
             }
+
+            for (File listedFile : listedFiles) {
+                matchFiles(listedFile, files, f, visitedDirectories);
+            }
+            return;
+        }
+
+        if (f.test(at)) {
+            files.add(at);
+        }
+    }
+
+    private String toCanonicalPath(File file) {
+        try {
+            return file.getCanonicalPath();
+        } catch (IOException ignored) {
+            return null;
         }
     }
 

core/src/main/java/art/arcane/iris/core/nms/INMSBinding.java

@@ -24,6 +24,7 @@ import art.arcane.iris.core.nms.container.BiomeColor;
 import art.arcane.iris.core.nms.container.BlockProperty;
 import art.arcane.iris.core.nms.container.StructurePlacement;
 import art.arcane.iris.core.nms.datapack.DataVersion;
+import art.arcane.iris.util.common.scheduling.J;
 import art.arcane.iris.engine.framework.Engine;
 import art.arcane.iris.engine.platform.PlatformChunkGenerator;
 import art.arcane.volmlib.util.collection.KList;
@@ -108,11 +109,13 @@ public interface INMSBinding {
                 return CompletableFuture.failedFuture(new IllegalStateException("Missing dimension types to create world"));
             }
 
-            FoliaWorldsLink link = FoliaWorldsLink.get();
-            if (link.isActive()) {
-                CompletableFuture<World> future = link.createWorld(c);
-                if (future != null) {
-                    return future;
+            if (J.isFolia()) {
+                FoliaWorldsLink link = FoliaWorldsLink.get();
+                if (link.isActive()) {
+                    CompletableFuture<World> future = link.createWorld(c);
+                    if (future != null) {
+                        return future;
+                    }
                 }
             }
             return CompletableFuture.completedFuture(createWorld(c));

core/src/main/java/art/arcane/iris/core/pregenerator/IrisPregenerator.java

@@ -19,6 +19,7 @@
 package art.arcane.iris.core.pregenerator;
 
 import art.arcane.iris.Iris;
+import art.arcane.iris.core.IrisSettings;
 import art.arcane.iris.core.tools.IrisPackBenchmarking;
 import art.arcane.volmlib.util.collection.KList;
 import art.arcane.volmlib.util.collection.KSet;
@@ -66,13 +67,14 @@ public class IrisPregenerator {
     private final KSet<Position2> retry;
     private final KSet<Position2> net;
     private final ChronoLatch cl;
-    private final ChronoLatch saveLatch = new ChronoLatch(30000);
+    private final ChronoLatch saveLatch;
     private final IrisPackBenchmarking benchmarking;
 
     public IrisPregenerator(PregenTask task, PregeneratorMethod generator, PregenListener listener) {
         benchmarking = IrisPackBenchmarking.getInstance();
         this.listener = listenify(listener);
         cl = new ChronoLatch(5000);
+        saveLatch = new ChronoLatch(IrisSettings.get().getPregen().getSaveIntervalMs());
         generatedRegions = new KSet<>();
         this.shutdown = new AtomicBoolean(false);
         this.paused = new AtomicBoolean(false);

core/src/main/java/art/arcane/iris/core/pregenerator/methods/AsyncPregenMethod.java

@@ -19,10 +19,13 @@
 package art.arcane.iris.core.pregenerator.methods;
 
 import art.arcane.iris.Iris;
+import art.arcane.iris.core.IrisPaperLikeBackendMode;
+import art.arcane.iris.core.IrisRuntimeSchedulerMode;
 import art.arcane.iris.core.IrisSettings;
 import art.arcane.iris.core.pregenerator.PregenListener;
 import art.arcane.iris.core.pregenerator.PregeneratorMethod;
 import art.arcane.iris.core.tools.IrisToolbelt;
+import art.arcane.iris.engine.framework.Engine;
 import art.arcane.volmlib.util.mantle.runtime.Mantle;
 import art.arcane.volmlib.util.matter.Matter;
 import art.arcane.volmlib.util.math.M;
@@ -33,6 +36,7 @@ import org.bukkit.Chunk;
 import org.bukkit.World;
 
 import java.lang.reflect.InvocationTargetException;
+import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutorService;
@@ -44,11 +48,13 @@ import java.util.concurrent.atomic.AtomicLong;
 
 public class AsyncPregenMethod implements PregeneratorMethod {
     private static final AtomicInteger THREAD_COUNT = new AtomicInteger();
-    private static final int FOLIA_MAX_CONCURRENCY = 32;
-    private static final int NON_FOLIA_MAX_CONCURRENCY = 96;
-    private static final int NON_FOLIA_CONCURRENCY_FACTOR = 2;
     private static final int ADAPTIVE_TIMEOUT_STEP = 3;
     private final World world;
+    private final IrisRuntimeSchedulerMode runtimeSchedulerMode;
+    private final IrisPaperLikeBackendMode paperLikeBackendMode;
+    private final boolean foliaRuntime;
+    private final String backendMode;
+    private final int workerPoolThreads;
     private final Executor executor;
     private final Semaphore semaphore;
     private final int threads;
@@ -68,6 +74,8 @@ public class AsyncPregenMethod implements PregeneratorMethod {
     private final AtomicLong failed = new AtomicLong();
     private final AtomicLong lastProgressAt = new AtomicLong(M.ms());
     private final AtomicLong lastPermitWaitLog = new AtomicLong(0L);
+    private final Object permitMonitor = new Object();
+    private volatile Engine metricsEngine;
 
     public AsyncPregenMethod(World world, int unusedThreads) {
         if (!PaperLib.isPaper()) {
@@ -75,20 +83,31 @@ public class AsyncPregenMethod implements PregeneratorMethod {
         }
 
         this.world = world;
-        if (J.isFolia()) {
+        IrisSettings.IrisSettingsPregen pregen = IrisSettings.get().getPregen();
+        this.runtimeSchedulerMode = IrisRuntimeSchedulerMode.resolve(pregen);
+        this.foliaRuntime = runtimeSchedulerMode == IrisRuntimeSchedulerMode.FOLIA;
+        if (foliaRuntime) {
+            this.paperLikeBackendMode = IrisPaperLikeBackendMode.AUTO;
+            this.backendMode = "folia-region";
             this.executor = new FoliaRegionExecutor();
         } else {
-            boolean useTicketQueue = IrisSettings.get().getPregen().isUseTicketQueue();
-            this.executor = useTicketQueue ? new TicketExecutor() : new ServiceExecutor();
+            this.paperLikeBackendMode = resolvePaperLikeBackendMode(pregen);
+            if (paperLikeBackendMode == IrisPaperLikeBackendMode.SERVICE) {
+                this.executor = new ServiceExecutor();
+                this.backendMode = "paper-service";
+            } else {
+                this.executor = new TicketExecutor();
+                this.backendMode = "paper-ticket";
+            }
         }
-        IrisSettings.IrisSettingsPregen pregen = IrisSettings.get().getPregen();
         int configuredThreads = pregen.getMaxConcurrency();
-        if (J.isFolia()) {
-            configuredThreads = Math.min(configuredThreads, FOLIA_MAX_CONCURRENCY);
+        if (foliaRuntime) {
+            configuredThreads = Math.min(configuredThreads, pregen.getFoliaMaxConcurrency());
         } else {
-            configuredThreads = Math.min(configuredThreads, resolveNonFoliaConcurrencyCap());
+            configuredThreads = Math.min(configuredThreads, resolvePaperLikeConcurrencyCap(pregen.getPaperLikeMaxConcurrency()));
         }
         this.threads = Math.max(1, configuredThreads);
+        this.workerPoolThreads = resolveWorkerPoolThreads();
         this.semaphore = new Semaphore(this.threads, true);
         this.timeoutSeconds = pregen.getChunkLoadTimeoutSeconds();
         this.timeoutWarnIntervalMs = pregen.getTimeoutWarnIntervalMs();
@@ -98,8 +117,32 @@ public class AsyncPregenMethod implements PregeneratorMethod {
         this.adaptiveMinInFlightLimit = Math.max(4, Math.min(16, Math.max(1, this.threads / 4)));
     }
 
+    private IrisPaperLikeBackendMode resolvePaperLikeBackendMode(IrisSettings.IrisSettingsPregen pregen) {
+        IrisPaperLikeBackendMode configuredMode = pregen.getPaperLikeBackendMode();
+        if (configuredMode != IrisPaperLikeBackendMode.AUTO) {
+            return configuredMode;
+        }
+
+        return pregen.isUseVirtualThreads() ? IrisPaperLikeBackendMode.SERVICE : IrisPaperLikeBackendMode.TICKET;
+    }
+
+    private int resolveWorkerPoolThreads() {
+        try {
+            Class<?> moonriseCommonClass = Class.forName("ca.spottedleaf.moonrise.common.util.MoonriseCommon");
+            java.lang.reflect.Field workerPoolField = moonriseCommonClass.getDeclaredField("WORKER_POOL");
+            Object workerPool = workerPoolField.get(null);
+            Object coreThreads = workerPool.getClass().getDeclaredMethod("getCoreThreads").invoke(workerPool);
+            if (coreThreads instanceof Thread[] threadsArray) {
+                return threadsArray.length;
+            }
+        } catch (Throwable ignored) {
+        }
+
+        return -1;
+    }
+
     private void unloadAndSaveAllChunks() {
-        if (J.isFolia()) {
+        if (foliaRuntime) {
             // Folia requires world/chunk mutations to be region-owned; periodic global unload/save is unsafe.
             lastUse.clear();
             return;
@@ -190,6 +233,7 @@ public class AsyncPregenMethod implements PregeneratorMethod {
             int next = Math.max(adaptiveMinInFlightLimit, current - 1);
             if (adaptiveInFlightLimit.compareAndSet(current, next)) {
                 logAdaptiveLimit("decrease", next);
+                notifyPermitWaiters();
                 return;
             }
         }
@@ -205,6 +249,7 @@ public class AsyncPregenMethod implements PregeneratorMethod {
             int next = Math.min(threads, current + 1);
             if (adaptiveInFlightLimit.compareAndSet(current, next)) {
                 logAdaptiveLimit("increase", next);
+                notifyPermitWaiters();
                 return;
             }
         }
@@ -222,11 +267,8 @@ public class AsyncPregenMethod implements PregeneratorMethod {
         }
     }
 
-    private int resolveNonFoliaConcurrencyCap() {
-        int worldGenThreads = Math.max(1, IrisSettings.get().getConcurrency().getWorldGenThreads());
-        int recommended = worldGenThreads * NON_FOLIA_CONCURRENCY_FACTOR;
-        int bounded = Math.max(8, Math.min(NON_FOLIA_MAX_CONCURRENCY, recommended));
-        return bounded;
+    private int resolvePaperLikeConcurrencyCap(int configuredCap) {
+        return Math.max(8, configuredCap);
     }
 
     private String metricsSnapshot() {
@@ -259,6 +301,48 @@ public class AsyncPregenMethod implements PregeneratorMethod {
         if (after < 0) {
             inFlight.compareAndSet(after, 0);
         }
+        notifyPermitWaiters();
+    }
+
+    private void notifyPermitWaiters() {
+        synchronized (permitMonitor) {
+            permitMonitor.notifyAll();
+        }
+    }
+
+    private void recordAdaptiveWait(long waitedMs) {
+        Engine engine = resolveMetricsEngine();
+        if (engine != null) {
+            engine.getMetrics().getPregenWaitAdaptive().put(waitedMs);
+        }
+    }
+
+    private void recordPermitWait(long waitedMs) {
+        Engine engine = resolveMetricsEngine();
+        if (engine != null) {
+            engine.getMetrics().getPregenWaitPermit().put(waitedMs);
+        }
+    }
+
+    private Engine resolveMetricsEngine() {
+        Engine cachedEngine = metricsEngine;
+        if (cachedEngine != null) {
+            return cachedEngine;
+        }
+
+        if (!IrisToolbelt.isIrisWorld(world)) {
+            return null;
+        }
+
+        try {
+            Engine resolvedEngine = IrisToolbelt.access(world).getEngine();
+            if (resolvedEngine != null) {
+                metricsEngine = resolvedEngine;
+            }
+            return resolvedEngine;
+        } catch (Throwable ignored) {
+            return null;
+        }
     }
 
     private void logPermitWaitIfNeeded(int x, int z, long waitedMs) {
@@ -276,9 +360,11 @@ public class AsyncPregenMethod implements PregeneratorMethod {
     @Override
     public void init() {
         Iris.info("Async pregen init: world=" + world.getName()
-                + ", mode=" + (J.isFolia() ? "folia" : "paper")
+                + ", mode=" + runtimeSchedulerMode.name().toLowerCase(Locale.ROOT)
+                + ", backend=" + backendMode
                 + ", threads=" + threads
                 + ", adaptiveLimit=" + adaptiveInFlightLimit.get()
+                + ", workerPoolThreads=" + workerPoolThreads
                 + ", urgent=" + urgent
                 + ", timeout=" + timeoutSeconds + "s");
         unloadAndSaveAllChunks();
@@ -318,17 +404,26 @@ public class AsyncPregenMethod implements PregeneratorMethod {
         listener.onChunkGenerating(x, z);
         try {
             long waitStart = M.ms();
-            while (inFlight.get() >= adaptiveInFlightLimit.get()) {
-                long waited = Math.max(0L, M.ms() - waitStart);
-                logPermitWaitIfNeeded(x, z, waited);
-                if (!J.sleep(5)) {
-                    return;
+            synchronized (permitMonitor) {
+                while (inFlight.get() >= adaptiveInFlightLimit.get()) {
+                    long waited = Math.max(0L, M.ms() - waitStart);
+                    logPermitWaitIfNeeded(x, z, waited);
+                    permitMonitor.wait(5000L);
                 }
             }
+            long adaptiveWait = Math.max(0L, M.ms() - waitStart);
+            if (adaptiveWait > 0L) {
+                recordAdaptiveWait(adaptiveWait);
+            }
 
+            long permitWaitStart = M.ms();
             while (!semaphore.tryAcquire(5, TimeUnit.SECONDS)) {
                 logPermitWaitIfNeeded(x, z, Math.max(0L, M.ms() - waitStart));
             }
+            long permitWait = Math.max(0L, M.ms() - permitWaitStart);
+            if (permitWait > 0L) {
+                recordPermitWait(permitWait);
+            }
         } catch (InterruptedException e) {
             Thread.currentThread().interrupt();
             return;

core/src/main/java/art/arcane/iris/core/project/IrisProject.java

@@ -33,6 +33,7 @@ import art.arcane.volmlib.util.collection.KList;
 import art.arcane.volmlib.util.collection.KMap;
 import art.arcane.volmlib.util.collection.KSet;
 import art.arcane.volmlib.util.exceptions.IrisException;
+import art.arcane.iris.util.common.format.C;
 import art.arcane.volmlib.util.format.Form;
 import art.arcane.volmlib.util.io.IO;
 import art.arcane.volmlib.util.json.JSONArray;
@@ -61,6 +62,8 @@ import java.util.Objects;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Consumer;
 
 @SuppressWarnings("ALL")
@@ -165,6 +168,11 @@ public class IrisProject {
         J.attemptAsync(() ->
         {
             try {
+                if (d == null) {
+                    sender.sendMessage("Could not load dimension \"" + getName() + "\"");
+                    return;
+                }
+
                 if (d.getLoader() == null) {
                     sender.sendMessage("Could not get dimension loader");
                     return;
@@ -176,12 +184,11 @@ public class IrisProject {
                     Iris.warn("Project missing code-workspace: " + ff.getAbsolutePath() + " Re-creating code workspace.");
 
                     try {
-                        IO.writeAll(ff, createCodeWorkspaceConfig());
+                        IO.writeAll(ff, createCodeWorkspaceConfig(false));
                     } catch (IOException e1) {
                         Iris.reportError(e1);
                         e1.printStackTrace();
                     }
-                    updateWorkspace();
                     if (!doOpenVSCode(f)) {
                         Iris.warn("Tried creating code workspace but failed a second time. Your project is likely corrupt.");
                     }
@@ -198,16 +205,20 @@ public class IrisProject {
         for (File i : Objects.requireNonNull(f.listFiles())) {
             if (i.getName().endsWith(".code-workspace")) {
                 foundWork = true;
-                J.a(() ->
-                {
-                    updateWorkspace();
-                });
 
                 if (IrisSettings.get().getStudio().isOpenVSCode()) {
                     if (!GraphicsEnvironment.isHeadless()) {
                         Iris.msg("Opening VSCode. You may see the output from VSCode.");
                         Iris.msg("VSCode output always starts with: '(node:#####) electron'");
-                        Desktop.getDesktop().open(i);
+                        Thread launcherThread = new Thread(() -> {
+                            try {
+                                Desktop.getDesktop().open(i);
+                            } catch (Throwable e) {
+                                Iris.reportError(e);
+                            }
+                        }, "Iris-VSCode-Launcher");
+                        launcherThread.setDaemon(true);
+                        launcherThread.start();
                     }
                 }
 
@@ -222,30 +233,121 @@ public class IrisProject {
             close();
         }
 
-        J.a(() -> {
-            IrisDimension d = IrisData.loadAnyDimension(getName(), null);
-            if (d == null) {
-                sender.sendMessage("Can't find dimension: " + getName());
-                return;
-            } else if (sender.isPlayer()) {
-                J.runEntity(sender.player(), () -> sender.player().setGameMode(GameMode.SPECTATOR));
-            }
+        AtomicReference<String> stage = new AtomicReference<>("Queued");
+        AtomicReference<Double> progress = new AtomicReference<>(0.01D);
+        AtomicBoolean complete = new AtomicBoolean(false);
+        AtomicBoolean failed = new AtomicBoolean(false);
+        startStudioOpenReporter(sender, stage, progress, complete, failed);
 
+        J.a(() -> {
+            World maintenanceWorld = null;
+            boolean maintenanceActive = false;
             try {
+                stage.set("Loading dimension");
+                progress.set(0.05D);
+                IrisDimension d = IrisData.loadAnyDimension(getName(), null);
+                if (d == null) {
+                    failed.set(true);
+                    sender.sendMessage(C.RED + "Can't find dimension: " + getName());
+                    return;
+                } else if (sender.isPlayer()) {
+                    J.runEntity(sender.player(), () -> sender.player().setGameMode(GameMode.SPECTATOR));
+                }
+
+                stage.set("Creating world");
+                progress.set(0.12D);
                 activeProvider = (PlatformChunkGenerator) IrisToolbelt.createWorld()
                         .seed(seed)
                         .sender(sender)
                         .studio(true)
                         .name("iris-" + UUID.randomUUID())
                         .dimension(d.getLoadKey())
+                        .studioProgressConsumer((value, currentStage) -> {
+                            if (currentStage != null && !currentStage.isBlank()) {
+                                stage.set(currentStage);
+                            }
+                            progress.set(Math.max(0D, Math.min(0.99D, value)));
+                        })
                         .create().getGenerator();
-                onDone.accept(activeProvider.getTarget().getWorld().realWorld());
+
+                if (activeProvider != null) {
+                    maintenanceWorld = activeProvider.getTarget().getWorld().realWorld();
+                    if (maintenanceWorld != null) {
+                        IrisToolbelt.beginWorldMaintenance(maintenanceWorld, "studio-open");
+                        maintenanceActive = true;
+                    }
+                    onDone.accept(maintenanceWorld);
+                }
             } catch (IrisException e) {
-                e.printStackTrace();
+                failed.set(true);
+                Iris.reportError(e);
+                sender.sendMessage(C.RED + "Failed to open studio world: " + e.getMessage());
+            } catch (Throwable e) {
+                failed.set(true);
+                Iris.reportError(e);
+                sender.sendMessage(C.RED + "Studio open failed: " + e.getMessage());
+            } finally {
+                if (activeProvider != null) {
+                    stage.set("Opening workspace");
+                    progress.set(Math.max(progress.get(), 0.95D));
+                    openVSCode(sender);
+                }
+
+                if (maintenanceActive && maintenanceWorld != null) {
+                    World worldToRelease = maintenanceWorld;
+                    J.a(() -> {
+                        J.sleep(15000);
+                        IrisToolbelt.endWorldMaintenance(worldToRelease, "studio-open");
+                    });
+                    maintenanceActive = false;
+                }
+
+                if (maintenanceActive && maintenanceWorld != null) {
+                    IrisToolbelt.endWorldMaintenance(maintenanceWorld, "studio-open");
+                }
+                complete.set(true);
+            }
+        });
+    }
+
+    private void startStudioOpenReporter(VolmitSender sender, AtomicReference<String> stage, AtomicReference<Double> progress, AtomicBoolean complete, AtomicBoolean failed) {
+        J.a(() -> {
+            String[] spinner = {"|", "/", "-", "\\"};
+            int spinIndex = 0;
+            long nextConsoleUpdate = 0L;
+
+            while (!complete.get()) {
+                double currentProgress = Math.max(0D, Math.min(0.97D, progress.get()));
+                String currentStage = stage.get();
+                String currentSpinner = spinner[spinIndex % spinner.length];
+
+                if (sender.isPlayer()) {
+                    sender.sendProgress(currentProgress, "Studio " + currentSpinner + " " + currentStage);
+                } else {
+                    long now = System.currentTimeMillis();
+                    if (now >= nextConsoleUpdate) {
+                        sender.sendMessage(C.WHITE + "Studio " + Form.pc(currentProgress, 0) + C.GRAY + " - " + currentStage);
+                        nextConsoleUpdate = now + 1500L;
+                    }
+                }
+
+                spinIndex++;
+                J.sleep(120);
             }
 
-            if (activeProvider != null) {
-                openVSCode(sender);
+            if (failed.get()) {
+                if (sender.isPlayer()) {
+                    sender.sendProgress(1D, "Studio open failed");
+                } else {
+                    sender.sendMessage(C.RED + "Studio open failed.");
+                }
+                return;
+            }
+
+            if (sender.isPlayer()) {
+                sender.sendProgress(1D, "Studio ready");
+            } else {
+                sender.sendMessage(C.GREEN + "Studio ready.");
             }
         });
     }
@@ -361,6 +463,10 @@ public class IrisProject {
     }
 
     public JSONObject createCodeWorkspaceConfig() {
+        return createCodeWorkspaceConfig(true);
+    }
+
+    private JSONObject createCodeWorkspaceConfig(boolean includeSchemas) {
         JSONObject ws = new JSONObject();
         JSONArray folders = new JSONArray();
         JSONObject folder = new JSONObject();
@@ -391,43 +497,50 @@ public class IrisProject {
         settings.put("[json]", jc);
         settings.put("json.maxItemsComputed", 30000);
         JSONArray schemas = new JSONArray();
-        IrisData dm = IrisData.get(getPath());
-
-        for (ResourceLoader<?> r : dm.getLoaders().v()) {
-            if (r.supportsSchemas()) {
-                schemas.put(r.buildSchema());
-            }
-        }
-
-        for (Class<?> i : dm.resolveSnippets()) {
-            try {
-                String snipType = i.getDeclaredAnnotation(Snippet.class).value();
-                JSONObject o = new JSONObject();
-                KList<String> fm = new KList<>();
-
-                for (int g = 1; g < 8; g++) {
-                    fm.add("/snippet/" + snipType + Form.repeat("/*", g) + ".json");
+        IrisData dm = null;
+        if (includeSchemas) {
+            dm = IrisData.get(getPath());
+            for (ResourceLoader<?> r : dm.getLoaders().v()) {
+                if (r.supportsSchemas()) {
+                    schemas.put(r.buildSchema());
                 }
+            }
 
-                o.put("fileMatch", new JSONArray(fm.toArray()));
-                o.put("url", "./.iris/schema/snippet/" + snipType + "-schema.json");
-                schemas.put(o);
-                File a = new File(dm.getDataFolder(), ".iris/schema/snippet/" + snipType + "-schema.json");
-                J.attemptAsync(() -> {
-                    try {
-                        IO.writeAll(a, new SchemaBuilder(i, dm).construct().toString(4));
-                    } catch (Throwable e) {
-                        e.printStackTrace();
+            for (Class<?> i : dm.resolveSnippets()) {
+                try {
+                    String snipType = i.getDeclaredAnnotation(Snippet.class).value();
+                    JSONObject o = new JSONObject();
+                    KList<String> fm = new KList<>();
+
+                    for (int g = 1; g < 8; g++) {
+                        fm.add("/snippet/" + snipType + Form.repeat("/*", g) + ".json");
                     }
-                });
-            } catch (Throwable e) {
-                e.printStackTrace();
+
+                    o.put("fileMatch", new JSONArray(fm.toArray()));
+                    o.put("url", "./.iris/schema/snippet/" + snipType + "-schema.json");
+                    schemas.put(o);
+                    IrisData snippetData = dm;
+                    File a = new File(snippetData.getDataFolder(), ".iris/schema/snippet/" + snipType + "-schema.json");
+                    J.attemptAsync(() -> {
+                        try {
+                            IO.writeAll(a, new SchemaBuilder(i, snippetData).construct().toString(4));
+                        } catch (Throwable e) {
+                            e.printStackTrace();
+                        }
+                    });
+                } catch (Throwable e) {
+                    e.printStackTrace();
+                }
             }
         }
 
         settings.put("json.schemas", schemas);
         ws.put("settings", settings);
 
+        if (!includeSchemas) {
+            return ws;
+        }
+
         File schemasFile = new File(path, ".idea" + File.separator + "jsonSchemas.xml");
         Document doc = IO.read(schemasFile);
         Element mappings = (Element) doc.selectSingleNode("//component[@name='JsonSchemaMappingsProjectConfiguration']");

core/src/main/java/art/arcane/iris/core/tools/IrisCreator.java

@@ -20,6 +20,7 @@ package art.arcane.iris.core.tools;
 
 import com.google.common.util.concurrent.AtomicDouble;
 import art.arcane.iris.Iris;
+import art.arcane.iris.core.IrisRuntimeSchedulerMode;
 import art.arcane.iris.core.IrisWorlds;
 import art.arcane.iris.core.IrisSettings;
 import art.arcane.iris.core.ServerConfigurator;
@@ -42,6 +43,7 @@ import art.arcane.volmlib.util.io.IO;
 import art.arcane.iris.util.common.plugin.VolmitSender;
 import art.arcane.iris.util.common.scheduling.J;
 import art.arcane.volmlib.util.scheduling.O;
+import art.arcane.volmlib.util.scheduling.FoliaScheduler;
 import io.papermc.lib.PaperLib;
 import lombok.Data;
 import lombok.experimental.Accessors;
@@ -60,6 +62,7 @@ import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.BiConsumer;
 import java.util.function.Function;
 import java.util.function.IntSupplier;
 
@@ -102,6 +105,7 @@ public class IrisCreator {
      * Benchmark mode
      */
     private boolean benchmark = false;
+    private BiConsumer<Double, String> studioProgressConsumer;
 
     public static boolean removeFromBukkitYml(String name) throws IOException {
         YamlConfiguration yml = YamlConfiguration.loadConfiguration(BUKKIT_YML);
@@ -132,6 +136,8 @@ public class IrisCreator {
             throw new IrisException("You cannot invoke create() on the main thread.");
         }
 
+        reportStudioProgress(0.02D, "Preparing studio open");
+
         if (studio()) {
             World existing = Bukkit.getWorld(name());
             if (existing == null) {
@@ -141,6 +147,7 @@ public class IrisCreator {
             }
         }
 
+        reportStudioProgress(0.08D, "Resolving dimension");
         IrisDimension d = IrisToolbelt.getDimension(dimension());
 
         if (d == null) {
@@ -150,11 +157,18 @@ public class IrisCreator {
         if (sender == null)
             sender = Iris.getSender();
 
+        reportStudioProgress(0.16D, "Preparing world pack");
         if (!studio() || benchmark) {
             Iris.service(StudioSVC.class).installIntoWorld(sender, d.getLoadKey(), new File(Bukkit.getWorldContainer(), name()));
         }
+        if (studio()) {
+            IrisRuntimeSchedulerMode runtimeSchedulerMode = IrisRuntimeSchedulerMode.resolve(IrisSettings.get().getPregen());
+            Iris.info("Studio create scheduling: mode=" + runtimeSchedulerMode.name().toLowerCase(Locale.ROOT)
+                    + ", regionizedRuntime=" + FoliaScheduler.isRegionizedRuntime(Bukkit.getServer()));
+        }
         prebakeNoisemapsBeforeWorldCreate(d);
 
+        reportStudioProgress(0.28D, "Installing datapacks");
         AtomicDouble pp = new AtomicDouble(0);
         O<Boolean> done = new O<>();
         done.set(false);
@@ -180,6 +194,7 @@ public class IrisCreator {
         if (ServerConfigurator.installDataPacks(verifyDataPacks, includeExternalDataPacks, extraWorldDatapackFoldersByPack)) {
             throw new IrisException("Datapacks were missing!");
         }
+        reportStudioProgress(0.40D, "Datapacks ready");
 
         PlatformChunkGenerator access = (PlatformChunkGenerator) wc.generator();
         if (access == null) throw new IrisException("Access is null. Something bad happened.");
@@ -195,7 +210,10 @@ public class IrisCreator {
                 int req = access.getSpawnChunks().join();
                 for (int c = 0; c < req && !done.get(); c = g.getAsInt()) {
                     double v = (double) c / req;
-                    if (sender.isPlayer()) {
+                    if (studioProgressConsumer != null) {
+                        reportStudioProgress(0.40D + (0.42D * v), "Generating spawn");
+                        J.sleep(16);
+                    } else if (sender.isPlayer()) {
                         sender.sendProgress(v, "Generating");
                         J.sleep(16);
                     } else {
@@ -208,6 +226,7 @@ public class IrisCreator {
 
 
         World world;
+        reportStudioProgress(0.46D, "Creating world");
         try {
             world = J.sfut(() -> INMS.get().createWorldAsync(wc))
                     .thenCompose(Function.identity())
@@ -224,6 +243,7 @@ public class IrisCreator {
         }
 
         done.set(true);
+        reportStudioProgress(0.86D, "World created");
 
         if (sender.isPlayer() && !benchmark) {
             Player senderPlayer = sender.player();
@@ -267,6 +287,7 @@ public class IrisCreator {
             addToBukkitYml();
             J.s(() -> Iris.linkMultiverseCore.updateWorld(world, dimension));
         }
+        reportStudioProgress(0.93D, "Applying world settings");
 
         if (pregen != null) {
             CompletableFuture<Boolean> ff = new CompletableFuture<>();
@@ -296,9 +317,24 @@ public class IrisCreator {
                 e.printStackTrace();
             }
         }
+        reportStudioProgress(0.98D, "Finalizing");
         return world;
     }
 
+    private void reportStudioProgress(double progress, String stage) {
+        BiConsumer<Double, String> consumer = studioProgressConsumer;
+        if (consumer == null) {
+            return;
+        }
+
+        double clamped = Math.max(0D, Math.min(1D, progress));
+        try {
+            consumer.accept(clamped, stage);
+        } catch (Throwable e) {
+            Iris.reportError(e);
+        }
+    }
+
     private void prebakeNoisemapsBeforeWorldCreate(IrisDimension dimension) {
         IrisSettings.IrisSettingsPregen pregenSettings = IrisSettings.get().getPregen();
         if (!pregenSettings.isStartupNoisemapPrebake()) {

core/src/main/java/art/arcane/iris/core/tools/IrisToolbelt.java

@@ -19,6 +19,7 @@
 package art.arcane.iris.core.tools;
 
 import art.arcane.iris.Iris;
+import art.arcane.iris.core.IrisRuntimeSchedulerMode;
 import art.arcane.iris.core.IrisSettings;
 import art.arcane.iris.core.gui.PregeneratorJob;
 import art.arcane.iris.core.loader.IrisData;
@@ -233,7 +234,11 @@ public class IrisToolbelt {
      */
     public static PregeneratorJob pregenerate(PregenTask task, PregeneratorMethod method, Engine engine, boolean cached) {
         applyPregenPerformanceProfile(engine);
-        boolean useCachedWrapper = cached && engine != null && !J.isFolia();
+        boolean useCachedWrapper = false;
+        if (cached && engine != null) {
+            IrisRuntimeSchedulerMode runtimeSchedulerMode = IrisRuntimeSchedulerMode.resolve(IrisSettings.get().getPregen());
+            useCachedWrapper = runtimeSchedulerMode != IrisRuntimeSchedulerMode.FOLIA;
+        }
         return new PregeneratorJob(task, useCachedWrapper ? new CachedPregenMethod(method, engine.getWorld().name()) : method, engine);
     }
 

core/src/main/java/art/arcane/iris/engine/IrisComplex.java

@@ -19,6 +19,7 @@
 package art.arcane.iris.engine;
 
 import art.arcane.iris.Iris;
+import art.arcane.iris.core.IrisHotPathMetricsMode;
 import art.arcane.iris.core.IrisSettings;
 import art.arcane.iris.core.loader.IrisData;
 import art.arcane.iris.engine.data.cache.Cache;
@@ -29,6 +30,7 @@ import art.arcane.iris.util.project.context.IrisContext;
 import art.arcane.iris.util.common.data.DataProvider;
 import art.arcane.volmlib.util.math.M;
 import art.arcane.volmlib.util.math.RNG;
+import art.arcane.iris.util.project.interpolation.IrisInterpolation.NoiseBounds;
 import art.arcane.iris.util.project.noise.CNG;
 import art.arcane.iris.util.project.stream.ProceduralStream;
 import art.arcane.iris.util.project.stream.interpolation.Interpolated;
@@ -47,6 +49,9 @@ import java.util.*;
 @ToString(exclude = "data")
 public class IrisComplex implements DataProvider {
     private static final BlockData AIR = Material.AIR.createBlockData();
+    private static final NoiseBounds ZERO_NOISE_BOUNDS = new NoiseBounds(0D, 0D);
+    private static final int HOT_PATH_METRICS_FLUSH_SIZE = 64;
+    private static final ThreadLocal<HotPathMetricsState> HOT_PATH_METRICS = ThreadLocal.withInitial(HotPathMetricsState::new);
     private RNG rng;
     private double fluidHeight;
     private IrisData data;
@@ -84,6 +89,7 @@ public class IrisComplex implements DataProvider {
     private IrisRegion focusRegion;
     private Map<IrisInterpolator, IdentityHashMap<IrisBiome, GeneratorBounds>> generatorBounds;
     private Set<IrisBiome> generatorBiomes;
+    private final Map<IrisBiome, ChildSelectionPlan> childSelectionPlans = Collections.synchronizedMap(new IdentityHashMap<>());
 
     public IrisComplex(Engine engine) {
         this(engine, false);
@@ -318,10 +324,15 @@ public class IrisComplex implements DataProvider {
             return 0;
         }
 
+        IrisSettings.IrisSettingsPregen pregen = IrisSettings.get().getPregen();
+        IrisHotPathMetricsMode metricsMode = pregen.getHotPathMetricsMode();
+        HotPathMetricsState metricsState = metricsMode == IrisHotPathMetricsMode.DISABLED ? null : HOT_PATH_METRICS.get();
+        boolean sampleMetrics = metricsState != null && metricsState.shouldSample(metricsMode, pregen.getHotPathMetricsSampleStride());
+        long interpolateStartNanos = sampleMetrics ? System.nanoTime() : 0L;
         CoordinateBiomeCache sampleCache = new CoordinateBiomeCache(64);
         IdentityHashMap<IrisBiome, GeneratorBounds> cachedBounds = generatorBounds.get(interpolator);
         IdentityHashMap<IrisBiome, GeneratorBounds> localBounds = new IdentityHashMap<>(8);
-        double hi = interpolator.interpolate(x, z, (xx, zz) -> {
+        NoiseBounds sampledBounds = interpolator.interpolateBounds(x, z, (xx, zz) -> {
             try {
                 IrisBiome bx = sampleCache.get(xx, zz);
                 if (bx == null) {
@@ -329,57 +340,32 @@ public class IrisComplex implements DataProvider {
                     sampleCache.put(xx, zz, bx);
                 }
 
-                GeneratorBounds bounds = cachedBounds == null ? null : cachedBounds.get(bx);
-                if (bounds == null) {
-                    bounds = localBounds.get(bx);
-                    if (bounds == null) {
-                        bounds = computeGeneratorBounds(engine, generators, bx);
-                        localBounds.put(bx, bounds);
-                    }
-                }
-
-                return bounds.max;
+                GeneratorBounds bounds = resolveGeneratorBounds(engine, generators, bx, cachedBounds, localBounds);
+                return bounds.noiseBounds;
             } catch (Throwable e) {
                 Iris.reportError(e);
                 e.printStackTrace();
-                Iris.error("Failed to sample hi biome at " + xx + " " + zz + "...");
+                Iris.error("Failed to sample interpolated biome bounds at " + xx + " " + zz + "...");
             }
 
-            return 0;
+            return ZERO_NOISE_BOUNDS;
         });
+        if (sampleMetrics) {
+            metricsState.recordInterpolate(engine, System.nanoTime() - interpolateStartNanos);
+        }
 
-        double lo = interpolator.interpolate(x, z, (xx, zz) -> {
-            try {
-                IrisBiome bx = sampleCache.get(xx, zz);
-                if (bx == null) {
-                    bx = baseBiomeStream.get(xx, zz);
-                    sampleCache.put(xx, zz, bx);
-                }
-
-                GeneratorBounds bounds = cachedBounds == null ? null : cachedBounds.get(bx);
-                if (bounds == null) {
-                    bounds = localBounds.get(bx);
-                    if (bounds == null) {
-                        bounds = computeGeneratorBounds(engine, generators, bx);
-                        localBounds.put(bx, bounds);
-                    }
-                }
-
-                return bounds.min;
-            } catch (Throwable e) {
-                Iris.reportError(e);
-                e.printStackTrace();
-                Iris.error("Failed to sample lo biome at " + xx + " " + zz + "...");
-            }
-
-            return 0;
-        });
+        double hi = sampledBounds.max();
+        double lo = sampledBounds.min();
 
+        long generatorStartNanos = sampleMetrics ? System.nanoTime() : 0L;
         double d = 0;
 
         for (IrisGenerator i : generators) {
             d += M.lerp(lo, hi, i.getHeight(x, z, seed + 239945));
         }
+        if (sampleMetrics) {
+            metricsState.recordGenerator(engine, System.nanoTime() - generatorStartNanos);
+        }
 
         return d / generators.size();
     }
@@ -443,6 +429,28 @@ public class IrisComplex implements DataProvider {
         return new GeneratorBounds(min, max);
     }
 
+    private GeneratorBounds resolveGeneratorBounds(
+            Engine engine,
+            Set<IrisGenerator> generators,
+            IrisBiome biome,
+            IdentityHashMap<IrisBiome, GeneratorBounds> cachedBounds,
+            IdentityHashMap<IrisBiome, GeneratorBounds> localBounds
+    ) {
+        GeneratorBounds bounds = cachedBounds == null ? null : cachedBounds.get(biome);
+        if (bounds != null) {
+            return bounds;
+        }
+
+        GeneratorBounds local = localBounds.get(biome);
+        if (local != null) {
+            return local;
+        }
+
+        GeneratorBounds computed = computeGeneratorBounds(engine, generators, biome);
+        localBounds.put(biome, computed);
+        return computed;
+    }
+
     private IrisBiome implode(IrisBiome b, Double x, Double z) {
         if (b.getChildren().isEmpty()) {
             return b;
@@ -461,20 +469,48 @@ public class IrisComplex implements DataProvider {
         }
 
         CNG childCell = b.getChildrenGenerator(rng, 123, b.getChildShrinkFactor());
-        KList<IrisBiome> chx = b.getRealChildren(this).copy();
-        chx.add(b);
-        IrisBiome biome = childCell.fitRarity(chx, x, z);
+        ChildSelectionPlan childSelectionPlan = resolveChildSelectionPlan(b);
+        IrisBiome biome = childSelectionPlan.select(childCell, x, z);
         biome.setInferredType(b.getInferredType());
         return implode(biome, x, z, max - 1);
     }
 
+    private ChildSelectionPlan resolveChildSelectionPlan(IrisBiome biome) {
+        ChildSelectionPlan cachedPlan = childSelectionPlans.get(biome);
+        if (cachedPlan != null) {
+            return cachedPlan;
+        }
+
+        synchronized (childSelectionPlans) {
+            ChildSelectionPlan synchronizedPlan = childSelectionPlans.get(biome);
+            if (synchronizedPlan != null) {
+                return synchronizedPlan;
+            }
+
+            KList<IrisBiome> children = biome.getRealChildren(this);
+            KList<IrisBiome> options = new KList<>();
+            for (IrisBiome child : children) {
+                if (child != null) {
+                    options.add(child);
+                }
+            }
+            options.add(biome);
+
+            ChildSelectionPlan createdPlan = ChildSelectionPlan.create(options);
+            childSelectionPlans.put(biome, createdPlan);
+            return createdPlan;
+        }
+    }
+
     private static class GeneratorBounds {
         private final double min;
         private final double max;
+        private final NoiseBounds noiseBounds;
 
         private GeneratorBounds(double min, double max) {
             this.min = min;
             this.max = max;
+            this.noiseBounds = new NoiseBounds(min, max);
         }
     }
 
@@ -528,6 +564,141 @@ public class IrisComplex implements DataProvider {
         }
     }
 
+    private static class ChildSelectionPlan {
+        private final IrisBiome[] mappedBiomes;
+        private final int maxIndex;
+
+        private ChildSelectionPlan(IrisBiome[] mappedBiomes) {
+            this.mappedBiomes = mappedBiomes;
+            this.maxIndex = mappedBiomes.length - 1;
+        }
+
+        private static ChildSelectionPlan create(KList<IrisBiome> options) {
+            if (options.isEmpty()) {
+                return new ChildSelectionPlan(new IrisBiome[0]);
+            }
+
+            int maxRarity = 1;
+            for (IrisBiome biome : options) {
+                if (biome != null && biome.getRarity() > maxRarity) {
+                    maxRarity = biome.getRarity();
+                }
+            }
+
+            int rarityMax = maxRarity + 1;
+            boolean flip = false;
+            KList<IrisBiome> mapped = new KList<>();
+            for (IrisBiome biome : options) {
+                if (biome == null) {
+                    continue;
+                }
+
+                int rarity = Math.max(1, biome.getRarity());
+                int count = rarityMax - rarity;
+                for (int index = 0; index < count; index++) {
+                    flip = !flip;
+                    if (flip) {
+                        mapped.add(biome);
+                    } else {
+                        mapped.add(0, biome);
+                    }
+                }
+            }
+
+            if (mapped.isEmpty()) {
+                IrisBiome[] fallback = new IrisBiome[]{options.get(0)};
+                return new ChildSelectionPlan(fallback);
+            }
+
+            IrisBiome[] mappedBiomes = mapped.toArray(new IrisBiome[0]);
+            return new ChildSelectionPlan(mappedBiomes);
+        }
+
+        private IrisBiome select(CNG childCell, double x, double z) {
+            if (mappedBiomes.length == 0) {
+                return null;
+            }
+
+            if (mappedBiomes.length == 1) {
+                return mappedBiomes[0];
+            }
+
+            int selectedIndex = childCell.fit2D(0, maxIndex, x, z);
+            if (selectedIndex < 0) {
+                return mappedBiomes[0];
+            }
+
+            if (selectedIndex > maxIndex) {
+                return mappedBiomes[maxIndex];
+            }
+
+            return mappedBiomes[selectedIndex];
+        }
+    }
+
+    private static class HotPathMetricsState {
+        private long callCounter;
+        private long interpolateNanos;
+        private int interpolateSamples;
+        private long generatorNanos;
+        private int generatorSamples;
+
+        private boolean shouldSample(IrisHotPathMetricsMode mode, int sampleStride) {
+            if (mode == IrisHotPathMetricsMode.EXACT) {
+                return true;
+            }
+
+            long current = callCounter++;
+            return (current & (sampleStride - 1L)) == 0L;
+        }
+
+        private void recordInterpolate(Engine engine, long nanos) {
+            if (nanos < 0L) {
+                return;
+            }
+
+            interpolateNanos += nanos;
+            interpolateSamples++;
+            if (interpolateSamples >= HOT_PATH_METRICS_FLUSH_SIZE) {
+                flushInterpolate(engine);
+            }
+        }
+
+        private void recordGenerator(Engine engine, long nanos) {
+            if (nanos < 0L) {
+                return;
+            }
+
+            generatorNanos += nanos;
+            generatorSamples++;
+            if (generatorSamples >= HOT_PATH_METRICS_FLUSH_SIZE) {
+                flushGenerator(engine);
+            }
+        }
+
+        private void flushInterpolate(Engine engine) {
+            if (interpolateSamples <= 0) {
+                return;
+            }
+
+            double averageMs = (interpolateNanos / (double) interpolateSamples) / 1_000_000D;
+            engine.getMetrics().getNoiseHeightInterpolate().put(averageMs);
+            interpolateNanos = 0L;
+            interpolateSamples = 0;
+        }
+
+        private void flushGenerator(Engine engine) {
+            if (generatorSamples <= 0) {
+                return;
+            }
+
+            double averageMs = (generatorNanos / (double) generatorSamples) / 1_000_000D;
+            engine.getMetrics().getNoiseHeightGenerator().put(averageMs);
+            generatorNanos = 0L;
+            generatorSamples = 0;
+        }
+    }
+
     public void close() {
 
     }

core/src/main/java/art/arcane/iris/engine/framework/Engine.java

@@ -324,6 +324,18 @@ public interface Engine extends DataProvider, Fallible, LootProvider, BlockUpdat
             return;
         }
 
+        if (!J.isFolia() && !J.isPrimaryThread()) {
+            CompletableFuture<?> scheduled = J.sfut(() -> updateChunk(c));
+            if (scheduled != null) {
+                try {
+                    scheduled.join();
+                } catch (Throwable e) {
+                    Iris.reportError(e);
+                }
+            }
+            return;
+        }
+
         var chunk = mantle.getChunk(c).use();
         try {
             Runnable tileTask = () -> {
@@ -424,7 +436,7 @@ public interface Engine extends DataProvider, Fallible, LootProvider, BlockUpdat
         }
 
         if (!J.isFolia()) {
-            return J.isPrimaryThread();
+            return true;
         }
 
         return J.isOwnedByCurrentRegion(chunk.getWorld(), chunk.getX(), chunk.getZ());

core/src/main/java/art/arcane/iris/engine/framework/EngineMetrics.java

@@ -39,6 +39,17 @@ public class EngineMetrics {
     private final AtomicRollingSequence deposit;
     private final AtomicRollingSequence carveResolve;
     private final AtomicRollingSequence carveApply;
+    private final AtomicRollingSequence noiseHeightInterpolate;
+    private final AtomicRollingSequence noiseHeightGenerator;
+    private final AtomicRollingSequence contextPrefill;
+    private final AtomicRollingSequence contextPrefillHeight;
+    private final AtomicRollingSequence contextPrefillBiome;
+    private final AtomicRollingSequence contextPrefillRock;
+    private final AtomicRollingSequence contextPrefillFluid;
+    private final AtomicRollingSequence contextPrefillRegion;
+    private final AtomicRollingSequence contextPrefillCave;
+    private final AtomicRollingSequence pregenWaitPermit;
+    private final AtomicRollingSequence pregenWaitAdaptive;
 
     public EngineMetrics(int mem) {
         this.total = new AtomicRollingSequence(mem);
@@ -56,6 +67,17 @@ public class EngineMetrics {
         this.deposit = new AtomicRollingSequence(mem);
         this.carveResolve = new AtomicRollingSequence(mem);
         this.carveApply = new AtomicRollingSequence(mem);
+        this.noiseHeightInterpolate = new AtomicRollingSequence(mem);
+        this.noiseHeightGenerator = new AtomicRollingSequence(mem);
+        this.contextPrefill = new AtomicRollingSequence(mem);
+        this.contextPrefillHeight = new AtomicRollingSequence(mem);
+        this.contextPrefillBiome = new AtomicRollingSequence(mem);
+        this.contextPrefillRock = new AtomicRollingSequence(mem);
+        this.contextPrefillFluid = new AtomicRollingSequence(mem);
+        this.contextPrefillRegion = new AtomicRollingSequence(mem);
+        this.contextPrefillCave = new AtomicRollingSequence(mem);
+        this.pregenWaitPermit = new AtomicRollingSequence(mem);
+        this.pregenWaitAdaptive = new AtomicRollingSequence(mem);
     }
 
     public KMap<String, Double> pull() {
@@ -75,6 +97,17 @@ public class EngineMetrics {
         v.put("deposit", deposit.getAverage());
         v.put("carve.resolve", carveResolve.getAverage());
         v.put("carve.apply", carveApply.getAverage());
+        v.put("noise.height.interpolate", noiseHeightInterpolate.getAverage());
+        v.put("noise.height.generator", noiseHeightGenerator.getAverage());
+        v.put("context.prefill", contextPrefill.getAverage());
+        v.put("context.prefill.height", contextPrefillHeight.getAverage());
+        v.put("context.prefill.biome", contextPrefillBiome.getAverage());
+        v.put("context.prefill.rock", contextPrefillRock.getAverage());
+        v.put("context.prefill.fluid", contextPrefillFluid.getAverage());
+        v.put("context.prefill.region", contextPrefillRegion.getAverage());
+        v.put("context.prefill.cave", contextPrefillCave.getAverage());
+        v.put("pregen.wait.permit", pregenWaitPermit.getAverage());
+        v.put("pregen.wait.adaptive", pregenWaitAdaptive.getAverage());
 
         return v;
     }

core/src/main/java/art/arcane/iris/engine/framework/EngineMode.java

@@ -78,7 +78,8 @@ public interface EngineMode extends Staged {
                 cacheContext = false;
             }
         }
-        ChunkContext ctx = new ChunkContext(x, z, getComplex(), cacheContext);
+        ChunkContext.PrefillPlan prefillPlan = cacheContext ? ChunkContext.PrefillPlan.NO_CAVE : ChunkContext.PrefillPlan.NONE;
+        ChunkContext ctx = new ChunkContext(x, z, getComplex(), cacheContext, prefillPlan, getEngine().getMetrics());
         IrisContext.getOr(getEngine()).setChunkContext(ctx);
 
         EngineStage[] stages = getStages().toArray(new EngineStage[0]);

core/src/main/java/art/arcane/iris/engine/mantle/components/IrisCaveCarver3D.java

@@ -25,12 +25,13 @@ import art.arcane.iris.engine.object.IrisCaveFieldModule;
 import art.arcane.iris.engine.object.IrisCaveProfile;
 import art.arcane.iris.engine.object.IrisRange;
 import art.arcane.iris.util.project.noise.CNG;
-import art.arcane.volmlib.util.collection.KList;
 import art.arcane.volmlib.util.math.RNG;
 import art.arcane.volmlib.util.matter.MatterCavern;
 import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
 
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 
 public class IrisCaveCarver3D {
     private static final byte LIQUID_AIR = 0;
@@ -46,7 +47,7 @@ public class IrisCaveCarver3D {
     private final CNG warpDensity;
     private final CNG surfaceBreakDensity;
     private final RNG thresholdRng;
-    private final KList<ModuleState> modules;
+    private final ModuleState[] modules;
     private final double normalization;
     private final MatterCavern carveAir;
     private final MatterCavern carveLava;
@@ -64,7 +65,7 @@ public class IrisCaveCarver3D {
         this.carveAir = new MatterCavern(true, "", LIQUID_AIR);
         this.carveLava = new MatterCavern(true, "", LIQUID_LAVA);
         this.carveForcedAir = new MatterCavern(true, "", LIQUID_FORCED_AIR);
-        this.modules = new KList<>();
+        List<ModuleState> moduleStates = new ArrayList<>();
 
         RNG baseRng = new RNG(engine.getSeedManager().getCarve());
         this.baseDensity = profile.getBaseDensityStyle().create(baseRng.nextParallelRNG(934_447), data);
@@ -82,13 +83,14 @@ public class IrisCaveCarver3D {
         for (IrisCaveFieldModule module : profile.getModules()) {
             CNG moduleDensity = module.getStyle().create(baseRng.nextParallelRNG(1_000_003L + (index * 65_537L)), data);
             ModuleState state = new ModuleState(module, moduleDensity);
-            modules.add(state);
+            moduleStates.add(state);
             weight += Math.abs(state.weight);
             index++;
         }
 
+        this.modules = moduleStates.toArray(new ModuleState[0]);
         normalization = weight <= 0 ? 1 : weight;
-        hasModules = !modules.isEmpty();
+        hasModules = modules.length > 0;
     }
 
     public int carve(MantleWriter writer, int chunkX, int chunkZ) {
@@ -171,7 +173,7 @@ public class IrisCaveCarver3D {
                     int columnSurfaceY = engine.getHeight(x, z);
                     int clearanceTopY = Math.min(maxY, Math.max(minY, columnSurfaceY - surfaceClearance));
                     boolean breakColumn = allowSurfaceBreak
-                            && signed(surfaceBreakDensity.noise(x, z)) >= surfaceBreakNoiseThreshold;
+                            && signed(surfaceBreakDensity.noiseFast2D(x, z)) >= surfaceBreakNoiseThreshold;
                     int columnTopY = breakColumn
                             ? Math.min(maxY, Math.max(minY, columnSurfaceY))
                             : clearanceTopY;
@@ -329,8 +331,8 @@ public class IrisCaveCarver3D {
 
     private double sampleDensity(int x, int y, int z) {
         if (!hasWarp && !hasModules) {
-            double density = signed(baseDensity.noise(x, y, z)) * baseWeight;
-            density += signed(detailDensity.noise(x, y, z)) * detailWeight;
+            double density = signed(baseDensity.noiseFast3D(x, y, z)) * baseWeight;
+            density += signed(detailDensity.noiseFast3D(x, y, z)) * detailWeight;
             return density / normalization;
         }
 
@@ -338,8 +340,8 @@ public class IrisCaveCarver3D {
         double warpedY = y;
         double warpedZ = z;
         if (hasWarp) {
-            double warpA = signed(warpDensity.noise(x, y, z));
-            double warpB = signed(warpDensity.noise(x + 31.37D, y - 17.21D, z + 23.91D));
+            double warpA = signed(warpDensity.noiseFast3D(x, y, z));
+            double warpB = signed(warpDensity.noiseFast3D(x + 31.37D, y - 17.21D, z + 23.91D));
             double offsetX = warpA * warpStrength;
             double offsetY = warpB * warpStrength;
             double offsetZ = (warpA - warpB) * 0.5D * warpStrength;
@@ -348,16 +350,17 @@ public class IrisCaveCarver3D {
             warpedZ += offsetZ;
         }
 
-        double density = signed(baseDensity.noise(warpedX, warpedY, warpedZ)) * baseWeight;
-        density += signed(detailDensity.noise(warpedX, warpedY, warpedZ)) * detailWeight;
+        double density = signed(baseDensity.noiseFast3D(warpedX, warpedY, warpedZ)) * baseWeight;
+        density += signed(detailDensity.noiseFast3D(warpedX, warpedY, warpedZ)) * detailWeight;
 
         if (hasModules) {
-            for (ModuleState module : modules) {
+            for (int moduleIndex = 0; moduleIndex < modules.length; moduleIndex++) {
+                ModuleState module = modules[moduleIndex];
                 if (y < module.minY || y > module.maxY) {
                     continue;
                 }
 
-                double moduleDensity = signed(module.density.noise(warpedX, warpedY, warpedZ)) - module.threshold;
+                double moduleDensity = signed(module.density.noiseFast3D(warpedX, warpedY, warpedZ)) - module.threshold;
                 if (module.invert) {
                     moduleDensity = -moduleDensity;
                 }

core/src/main/java/art/arcane/iris/engine/mantle/components/MantleCarvingComponent.java

@@ -18,6 +18,7 @@
 
 package art.arcane.iris.engine.mantle.components;
 
+import art.arcane.iris.engine.data.cache.Cache;
 import art.arcane.iris.engine.mantle.ComponentFlag;
 import art.arcane.iris.engine.mantle.EngineMantle;
 import art.arcane.iris.engine.mantle.IrisMantleComponent;
@@ -32,6 +33,7 @@ import art.arcane.iris.util.project.context.ChunkContext;
 import art.arcane.volmlib.util.documentation.ChunkCoordinates;
 import art.arcane.volmlib.util.mantle.flag.ReservedFlag;
 import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
+import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 
 import java.util.ArrayList;
 import java.util.Comparator;
@@ -75,8 +77,9 @@ public class MantleCarvingComponent extends IrisMantleComponent {
     @Override
     public void generateLayer(MantleWriter writer, int x, int z, ChunkContext context) {
         IrisDimensionCarvingResolver.State resolverState = new IrisDimensionCarvingResolver.State();
+        Long2ObjectOpenHashMap<IrisBiome> caveBiomeCache = new Long2ObjectOpenHashMap<>(FIELD_SIZE * FIELD_SIZE);
         PrecisionStopwatch resolveStopwatch = PrecisionStopwatch.start();
-        List<WeightedProfile> weightedProfiles = resolveWeightedProfiles(x, z, resolverState);
+        List<WeightedProfile> weightedProfiles = resolveWeightedProfiles(x, z, resolverState, caveBiomeCache);
         getEngineMantle().getEngine().getMetrics().getCarveResolve().put(resolveStopwatch.getMilliseconds());
         for (WeightedProfile weightedProfile : weightedProfiles) {
             carveProfile(weightedProfile, writer, x, z);
@@ -89,8 +92,8 @@ public class MantleCarvingComponent extends IrisMantleComponent {
         carver.carve(writer, cx, cz, weightedProfile.columnWeights, MIN_WEIGHT, THRESHOLD_PENALTY, weightedProfile.worldYRange);
     }
 
-    private List<WeightedProfile> resolveWeightedProfiles(int chunkX, int chunkZ, IrisDimensionCarvingResolver.State resolverState) {
-        IrisCaveProfile[] profileField = buildProfileField(chunkX, chunkZ, resolverState);
+    private List<WeightedProfile> resolveWeightedProfiles(int chunkX, int chunkZ, IrisDimensionCarvingResolver.State resolverState, Long2ObjectOpenHashMap<IrisBiome> caveBiomeCache) {
+        IrisCaveProfile[] profileField = buildProfileField(chunkX, chunkZ, resolverState, caveBiomeCache);
         Map<IrisCaveProfile, double[]> profileWeights = new IdentityHashMap<>();
         IrisCaveProfile[] columnProfiles = new IrisCaveProfile[KERNEL_SIZE];
         double[] columnProfileWeights = new double[KERNEL_SIZE];
@@ -215,7 +218,7 @@ public class MantleCarvingComponent extends IrisMantleComponent {
         return weightedProfiles;
     }
 
-    private IrisCaveProfile[] buildProfileField(int chunkX, int chunkZ, IrisDimensionCarvingResolver.State resolverState) {
+    private IrisCaveProfile[] buildProfileField(int chunkX, int chunkZ, IrisDimensionCarvingResolver.State resolverState, Long2ObjectOpenHashMap<IrisBiome> caveBiomeCache) {
         IrisCaveProfile[] profileField = new IrisCaveProfile[FIELD_SIZE * FIELD_SIZE];
         int startX = (chunkX << 4) - BLEND_RADIUS;
         int startZ = (chunkZ << 4) - BLEND_RADIUS;
@@ -224,7 +227,7 @@ public class MantleCarvingComponent extends IrisMantleComponent {
             int worldX = startX + fieldX;
             for (int fieldZ = 0; fieldZ < FIELD_SIZE; fieldZ++) {
                 int worldZ = startZ + fieldZ;
-                profileField[(fieldX * FIELD_SIZE) + fieldZ] = resolveColumnProfile(worldX, worldZ, resolverState);
+                profileField[(fieldX * FIELD_SIZE) + fieldZ] = resolveColumnProfile(worldX, worldZ, resolverState, caveBiomeCache);
             }
         }
 
@@ -241,7 +244,7 @@ public class MantleCarvingComponent extends IrisMantleComponent {
         return -1;
     }
 
-    private IrisCaveProfile resolveColumnProfile(int worldX, int worldZ, IrisDimensionCarvingResolver.State resolverState) {
+    private IrisCaveProfile resolveColumnProfile(int worldX, int worldZ, IrisDimensionCarvingResolver.State resolverState, Long2ObjectOpenHashMap<IrisBiome> caveBiomeCache) {
         IrisCaveProfile resolved = null;
         IrisCaveProfile dimensionProfile = getDimension().getCaveProfile();
         if (isProfileEnabled(dimensionProfile)) {
@@ -266,7 +269,14 @@ public class MantleCarvingComponent extends IrisMantleComponent {
 
         int surfaceY = getEngineMantle().getEngine().getHeight(worldX, worldZ, true);
         int sampleY = Math.max(1, surfaceY - 56);
-        IrisBiome caveBiome = getEngineMantle().getEngine().getCaveBiome(worldX, sampleY, worldZ, resolverState);
+        long cacheKey = Cache.key(worldX, worldZ);
+        IrisBiome caveBiome = caveBiomeCache.get(cacheKey);
+        if (caveBiome == null) {
+            caveBiome = getEngineMantle().getEngine().getCaveBiome(worldX, sampleY, worldZ, resolverState);
+            if (caveBiome != null) {
+                caveBiomeCache.put(cacheKey, caveBiome);
+            }
+        }
         if (caveBiome != null) {
             IrisCaveProfile caveProfile = caveBiome.getCaveProfile();
             if (isProfileEnabled(caveProfile)) {

core/src/main/java/art/arcane/iris/engine/modifier/IrisCarveModifier.java

@@ -33,12 +33,14 @@ import art.arcane.iris.util.project.hunk.Hunk;
 import art.arcane.volmlib.util.collection.KList;
 import art.arcane.volmlib.util.mantle.runtime.Mantle;
 import art.arcane.volmlib.util.mantle.runtime.MantleChunk;
+import art.arcane.volmlib.util.math.BlockPosition;
 import art.arcane.volmlib.util.math.M;
 import art.arcane.volmlib.util.math.RNG;
 import art.arcane.volmlib.util.matter.Matter;
 import art.arcane.volmlib.util.matter.MatterCavern;
 import art.arcane.volmlib.util.matter.slices.MarkerMatter;
 import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
+import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import lombok.Data;
 import org.bukkit.Material;
 import org.bukkit.block.data.BlockData;
@@ -64,6 +66,7 @@ public class IrisCarveModifier extends EngineAssignedModifier<BlockData> {
         Mantle<Matter> mantle = getEngine().getMantle().getMantle();
         MantleChunk<Matter> mc = mantle.getChunk(x, z).use();
         IrisDimensionCarvingResolver.State resolverState = new IrisDimensionCarvingResolver.State();
+        Long2ObjectOpenHashMap<IrisBiome> caveBiomeCache = new Long2ObjectOpenHashMap<>(2048);
         int[][] columnHeights = new int[256][];
         int[] columnHeightSizes = new int[256];
         PackedWallBuffer walls = new PackedWallBuffer(512);
@@ -129,7 +132,7 @@ public class IrisCarveModifier extends EngineAssignedModifier<BlockData> {
                     int worldX = rx + (x << 4);
                     int worldZ = rz + (z << 4);
                     IrisBiome biome = cavern.getCustomBiome().isEmpty()
-                            ? getEngine().getCaveBiome(worldX, yy, worldZ, resolverState)
+                            ? resolveCaveBiome(caveBiomeCache, worldX, yy, worldZ, resolverState)
                             : getEngine().getData().getBiomeLoader().load(cavern.getCustomBiome());
 
                     if (biome != null) {
@@ -166,7 +169,7 @@ public class IrisCarveModifier extends EngineAssignedModifier<BlockData> {
                             buf = y;
                             zone.ceiling = buf;
                         } else if (zone.isValid(getEngine())) {
-                            processZone(output, mc, mantle, zone, rx, rz, rx + (x << 4), rz + (z << 4), resolverState);
+                            processZone(output, mc, mantle, zone, rx, rz, rx + (x << 4), rz + (z << 4), resolverState, caveBiomeCache);
                             zone = new CaveZone();
                             zone.setFloor(y);
                             buf = y;
@@ -178,7 +181,7 @@ public class IrisCarveModifier extends EngineAssignedModifier<BlockData> {
                     }
 
                     if (zone.isValid(getEngine())) {
-                        processZone(output, mc, mantle, zone, rx, rz, rx + (x << 4), rz + (z << 4), resolverState);
+                        processZone(output, mc, mantle, zone, rx, rz, rx + (x << 4), rz + (z << 4), resolverState, caveBiomeCache);
                     }
                 }
             } finally {
@@ -190,7 +193,7 @@ public class IrisCarveModifier extends EngineAssignedModifier<BlockData> {
         }
     }
 
-    private void processZone(Hunk<BlockData> output, MantleChunk<Matter> mc, Mantle<Matter> mantle, CaveZone zone, int rx, int rz, int xx, int zz, IrisDimensionCarvingResolver.State resolverState) {
+    private void processZone(Hunk<BlockData> output, MantleChunk<Matter> mc, Mantle<Matter> mantle, CaveZone zone, int rx, int rz, int xx, int zz, IrisDimensionCarvingResolver.State resolverState, Long2ObjectOpenHashMap<IrisBiome> caveBiomeCache) {
         int center = (zone.floor + zone.ceiling) / 2;
         String customBiome = "";
 
@@ -221,7 +224,7 @@ public class IrisCarveModifier extends EngineAssignedModifier<BlockData> {
         }
 
         IrisBiome biome = customBiome.isEmpty()
-                ? getEngine().getCaveBiome(xx, center, zz, resolverState)
+                ? resolveCaveBiome(caveBiomeCache, xx, center, zz, resolverState)
                 : getEngine().getData().getBiomeLoader().load(customBiome);
 
         if (biome == null) {
@@ -286,6 +289,20 @@ public class IrisCarveModifier extends EngineAssignedModifier<BlockData> {
         }
     }
 
+    private IrisBiome resolveCaveBiome(Long2ObjectOpenHashMap<IrisBiome> caveBiomeCache, int x, int y, int z, IrisDimensionCarvingResolver.State resolverState) {
+        long key = BlockPosition.toLong(x, y, z);
+        IrisBiome cachedBiome = caveBiomeCache.get(key);
+        if (cachedBiome != null) {
+            return cachedBiome;
+        }
+
+        IrisBiome resolvedBiome = getEngine().getCaveBiome(x, y, z, resolverState);
+        if (resolvedBiome != null) {
+            caveBiomeCache.put(key, resolvedBiome);
+        }
+        return resolvedBiome;
+    }
+
     private void appendColumnHeight(int[][] heights, int[] sizes, int columnIndex, int y) {
         int[] column = heights[columnIndex];
         int size = sizes[columnIndex];

core/src/main/java/art/arcane/iris/engine/object/IrisDimensionCarvingResolver.java

@@ -1,6 +1,7 @@
 package art.arcane.iris.engine.object;
 
 import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.util.project.interpolation.IrisInterpolation;
 import art.arcane.volmlib.util.collection.KList;
 import art.arcane.iris.util.project.noise.CNG;
 
@@ -153,7 +154,8 @@ public final class IrisDimensionCarvingResolver {
 
         long seed = resolveChildSeed(engine, state);
         CNG childGenerator = parent.getChildrenGenerator(seed, engine.getData());
-        int selectedIndex = childGenerator.fit(0, selectionPlan.maxIndex, worldX, worldZ);
+        double sample = childGenerator.noiseFast2D(worldX, worldZ);
+        int selectedIndex = (int) Math.round(IrisInterpolation.lerp(0, selectionPlan.maxIndex, sample));
         CarvingChoice selected = selectionPlan.get(selectedIndex);
         if (selected == null || selected.entry == null) {
             return parent;

core/src/main/java/art/arcane/iris/engine/object/IrisInterpolator.java

@@ -25,6 +25,8 @@ import art.arcane.iris.engine.object.annotations.Required;
 import art.arcane.volmlib.util.function.NoiseProvider;
 import art.arcane.iris.util.project.interpolation.InterpolationMethod;
 import art.arcane.iris.util.project.interpolation.IrisInterpolation;
+import art.arcane.iris.util.project.interpolation.IrisInterpolation.NoiseBounds;
+import art.arcane.iris.util.project.interpolation.IrisInterpolation.NoiseBoundsProvider;
 import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.NoArgsConstructor;
@@ -71,4 +73,12 @@ public class IrisInterpolator {
     public double interpolate(int x, int z, NoiseProvider provider) {
         return IrisInterpolation.getNoise(getFunction(), x, z, getHorizontalScale(), provider);
     }
+
+    public NoiseBounds interpolateBounds(double x, double z, NoiseBoundsProvider provider) {
+        return interpolateBounds((int) Math.round(x), (int) Math.round(z), provider);
+    }
+
+    public NoiseBounds interpolateBounds(int x, int z, NoiseBoundsProvider provider) {
+        return IrisInterpolation.getNoiseBounds(getFunction(), x, z, getHorizontalScale(), provider);
+    }
 }

core/src/main/java/art/arcane/iris/engine/object/IrisNoiseGenerator.java

@@ -106,7 +106,8 @@ public class IrisNoiseGenerator {
             g += 819;
         }
 
-        double n = getGenerator(superSeed, data).fitDouble(0, opacity, (x / zoom) + offsetX, (z / zoom) + offsetZ);
+        CNG cng = getGenerator(superSeed, data);
+        double n = cng.noiseFast2D((x / zoom) + offsetX, (z / zoom) + offsetZ) * opacity;
         n = negative ? (-n + opacity) : n;
         n = (exponent != 1 ? n < 0 ? -Math.pow(-n, exponent) : Math.pow(n, exponent) : n) + offsetY;
         n = parametric ? IrisInterpolation.parametric(n, 1) : n;

core/src/main/java/art/arcane/iris/util/common/scheduling/J.java

@@ -168,7 +168,7 @@ public class J {
     }
 
     public static boolean isFolia() {
-        return FoliaScheduler.isFolia(Iris.instance);
+        return FoliaScheduler.isFolia(Bukkit.getServer());
     }
 
     public static boolean isPrimaryThread() {
@@ -176,10 +176,26 @@ public class J {
     }
 
     public static boolean isOwnedByCurrentRegion(Entity entity) {
+        if (entity == null) {
+            return false;
+        }
+
+        if (!isFolia()) {
+            return isPrimaryThread();
+        }
+
         return FoliaScheduler.isOwnedByCurrentRegion(entity);
     }
 
     public static boolean isOwnedByCurrentRegion(World world, int chunkX, int chunkZ) {
+        if (world == null) {
+            return false;
+        }
+
+        if (!isFolia()) {
+            return isPrimaryThread();
+        }
+
         return FoliaScheduler.isOwnedByCurrentRegion(world, chunkX, chunkZ);
     }
 
@@ -531,34 +547,66 @@ public class J {
     }
 
     private static boolean runGlobalImmediate(Runnable runnable) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runGlobal(Iris.instance, runnable);
     }
 
     private static boolean runGlobalDelayed(Runnable runnable, int delayTicks) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runGlobal(Iris.instance, runnable, Math.max(0, delayTicks));
     }
 
     private static boolean runRegionImmediate(World world, int chunkX, int chunkZ, Runnable runnable) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runRegion(Iris.instance, world, chunkX, chunkZ, runnable);
     }
 
     private static boolean runRegionDelayed(World world, int chunkX, int chunkZ, Runnable runnable, int delayTicks) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runRegion(Iris.instance, world, chunkX, chunkZ, runnable, Math.max(0, delayTicks));
     }
 
     private static boolean runAsyncImmediate(Runnable runnable) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runAsync(Iris.instance, runnable);
     }
 
     private static boolean runAsyncDelayed(Runnable runnable, int delayTicks) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runAsync(Iris.instance, runnable, Math.max(0, delayTicks));
     }
 
     private static boolean runEntityImmediate(Entity entity, Runnable runnable) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runEntity(Iris.instance, entity, runnable);
     }
 
     private static boolean runEntityDelayed(Entity entity, Runnable runnable, int delayTicks) {
+        if (!isFolia()) {
+            return false;
+        }
+
         return FoliaScheduler.runEntity(Iris.instance, entity, runnable, Math.max(0, delayTicks));
     }
 

core/src/main/java/art/arcane/iris/util/project/context/ChunkContext.java

@@ -1,17 +1,19 @@
 package art.arcane.iris.util.project.context;
 
+import art.arcane.iris.core.IrisHotPathMetricsMode;
+import art.arcane.iris.core.IrisSettings;
 import art.arcane.iris.engine.IrisComplex;
+import art.arcane.iris.engine.framework.EngineMetrics;
 import art.arcane.iris.engine.object.IrisBiome;
 import art.arcane.iris.engine.object.IrisRegion;
-import art.arcane.iris.util.common.parallel.MultiBurst;
+import art.arcane.volmlib.util.atomics.AtomicRollingSequence;
 import org.bukkit.block.data.BlockData;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.Executor;
+import java.util.IdentityHashMap;
 
 public class ChunkContext {
+    private static final int PREFILL_METRICS_FLUSH_SIZE = 64;
+    private static final ThreadLocal<PrefillMetricsState> PREFILL_METRICS = ThreadLocal.withInitial(PrefillMetricsState::new);
     private final int x;
     private final int z;
     private final ChunkedDataCache<Double> height;
@@ -22,10 +24,18 @@ public class ChunkContext {
     private final ChunkedDataCache<IrisRegion> region;
 
     public ChunkContext(int x, int z, IrisComplex complex) {
-        this(x, z, complex, true);
+        this(x, z, complex, true, PrefillPlan.NO_CAVE, null);
     }
 
     public ChunkContext(int x, int z, IrisComplex complex, boolean cache) {
+        this(x, z, complex, cache, PrefillPlan.NO_CAVE, null);
+    }
+
+    public ChunkContext(int x, int z, IrisComplex complex, boolean cache, EngineMetrics metrics) {
+        this(x, z, complex, cache, PrefillPlan.NO_CAVE, metrics);
+    }
+
+    public ChunkContext(int x, int z, IrisComplex complex, boolean cache, PrefillPlan prefillPlan, EngineMetrics metrics) {
         this.x = x;
         this.z = z;
         this.height = new ChunkedDataCache<>(complex.getHeightStream(), x, z, cache);
@@ -36,17 +46,42 @@ public class ChunkContext {
         this.region = new ChunkedDataCache<>(complex.getRegionStream(), x, z, cache);
 
         if (cache) {
-            Executor executor = MultiBurst.burst;
-            List<CompletableFuture<Void>> tasks = new ArrayList<>(6);
-            tasks.add(CompletableFuture.runAsync(() -> height.fill(executor), executor));
-            tasks.add(CompletableFuture.runAsync(() -> biome.fill(executor), executor));
-            tasks.add(CompletableFuture.runAsync(() -> cave.fill(executor), executor));
-            tasks.add(CompletableFuture.runAsync(() -> rock.fill(executor), executor));
-            tasks.add(CompletableFuture.runAsync(() -> fluid.fill(executor), executor));
-            tasks.add(CompletableFuture.runAsync(() -> region.fill(executor), executor));
-            for (CompletableFuture<Void> task : tasks) {
-                task.join();
+            PrefillPlan resolvedPlan = prefillPlan == null ? PrefillPlan.NO_CAVE : prefillPlan;
+            PrefillMetricsState metricsState = PREFILL_METRICS.get();
+            IrisSettings.IrisSettingsPregen pregen = IrisSettings.get().getPregen();
+            IrisHotPathMetricsMode metricsMode = pregen.getHotPathMetricsMode();
+            boolean sampleMetrics = metricsMode != IrisHotPathMetricsMode.DISABLED
+                    && metricsState.shouldSample(metricsMode, pregen.getHotPathMetricsSampleStride());
+            long totalStartNanos = sampleMetrics ? System.nanoTime() : 0L;
+            if (resolvedPlan.height) {
+                fill(height, metrics == null ? null : metrics.getContextPrefillHeight(), sampleMetrics, metricsState);
             }
+            if (resolvedPlan.biome) {
+                fill(biome, metrics == null ? null : metrics.getContextPrefillBiome(), sampleMetrics, metricsState);
+            }
+            if (resolvedPlan.rock) {
+                fill(rock, metrics == null ? null : metrics.getContextPrefillRock(), sampleMetrics, metricsState);
+            }
+            if (resolvedPlan.fluid) {
+                fill(fluid, metrics == null ? null : metrics.getContextPrefillFluid(), sampleMetrics, metricsState);
+            }
+            if (resolvedPlan.region) {
+                fill(region, metrics == null ? null : metrics.getContextPrefillRegion(), sampleMetrics, metricsState);
+            }
+            if (resolvedPlan.cave) {
+                fill(cave, metrics == null ? null : metrics.getContextPrefillCave(), sampleMetrics, metricsState);
+            }
+            if (metrics != null && sampleMetrics) {
+                metricsState.record(metrics.getContextPrefill(), System.nanoTime() - totalStartNanos);
+            }
+        }
+    }
+
+    private void fill(ChunkedDataCache<?> dataCache, AtomicRollingSequence metrics, boolean sampleMetrics, PrefillMetricsState metricsState) {
+        long startNanos = sampleMetrics ? System.nanoTime() : 0L;
+        dataCache.fill();
+        if (metrics != null && sampleMetrics) {
+            metricsState.record(metrics, System.nanoTime() - startNanos);
         }
     }
 
@@ -81,4 +116,66 @@ public class ChunkContext {
     public ChunkedDataCache<IrisRegion> getRegion() {
         return region;
     }
+
+    public enum PrefillPlan {
+        ALL(true, true, true, true, true, true),
+        NO_CAVE(true, true, false, true, true, true),
+        NONE(false, false, false, false, false, false);
+
+        private final boolean height;
+        private final boolean biome;
+        private final boolean cave;
+        private final boolean rock;
+        private final boolean fluid;
+        private final boolean region;
+
+        PrefillPlan(boolean height, boolean biome, boolean cave, boolean rock, boolean fluid, boolean region) {
+            this.height = height;
+            this.biome = biome;
+            this.cave = cave;
+            this.rock = rock;
+            this.fluid = fluid;
+            this.region = region;
+        }
+    }
+
+    private static final class PrefillMetricsState {
+        private long callCounter;
+        private final IdentityHashMap<AtomicRollingSequence, MetricBucket> buckets = new IdentityHashMap<>();
+
+        private boolean shouldSample(IrisHotPathMetricsMode mode, int sampleStride) {
+            if (mode == IrisHotPathMetricsMode.EXACT) {
+                return true;
+            }
+
+            long current = callCounter++;
+            return (current & (sampleStride - 1L)) == 0L;
+        }
+
+        private void record(AtomicRollingSequence sequence, long nanos) {
+            if (sequence == null || nanos < 0L) {
+                return;
+            }
+
+            MetricBucket bucket = buckets.get(sequence);
+            if (bucket == null) {
+                bucket = new MetricBucket();
+                buckets.put(sequence, bucket);
+            }
+
+            bucket.nanos += nanos;
+            bucket.samples++;
+            if (bucket.samples >= PREFILL_METRICS_FLUSH_SIZE) {
+                double averageMs = (bucket.nanos / (double) bucket.samples) / 1_000_000D;
+                sequence.put(averageMs);
+                bucket.nanos = 0L;
+                bucket.samples = 0;
+            }
+        }
+    }
+
+    private static final class MetricBucket {
+        private long nanos;
+        private int samples;
+    }
 }

core/src/main/java/art/arcane/iris/util/project/context/ChunkedDataCache.java

@@ -1,13 +1,9 @@
 package art.arcane.iris.util.project.context;
 
 import art.arcane.iris.util.project.stream.ProceduralStream;
+import art.arcane.iris.util.project.stream.utility.CachedStream2D;
 import art.arcane.volmlib.util.documentation.BlockCoordinates;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ForkJoinPool;
 
 public class ChunkedDataCache<T> {
     private final int x;
@@ -31,7 +27,7 @@ public class ChunkedDataCache<T> {
     }
 
     public void fill() {
-        fill(ForkJoinPool.commonPool());
+        fill(null);
     }
 
     public void fill(Executor executor) {
@@ -39,20 +35,17 @@ public class ChunkedDataCache<T> {
             return;
         }
 
-        List<CompletableFuture<Void>> tasks = new ArrayList<>(16);
-        for (int j = 0; j < 16; j++) {
-            int row = j;
-            tasks.add(CompletableFuture.runAsync(() -> {
-                int rowOffset = row * 16;
-                double zz = (z + row);
-                for (int i = 0; i < 16; i++) {
-                    data[rowOffset + i] = stream.get(x + i, zz);
-                }
-            }, executor));
+        if (stream instanceof CachedStream2D<?> cachedStream) {
+            cachedStream.fillChunk(x, z, data);
+            return;
         }
 
-        for (CompletableFuture<Void> task : tasks) {
-            task.join();
+        for (int row = 0; row < 16; row++) {
+            int rowOffset = row * 16;
+            int worldZ = z + row;
+            for (int column = 0; column < 16; column++) {
+                data[rowOffset + column] = stream.get(x + column, worldZ);
+            }
         }
     }
 
@@ -63,11 +56,14 @@ public class ChunkedDataCache<T> {
             return stream.get(this.x + x, this.z + z);
         }
 
-        T value = (T) data[(z * 16) + x];
+        int index = (z * 16) + x;
+        T value = (T) data[index];
         if (value != null) {
             return value;
         }
 
-        return stream.get(this.x + x, this.z + z);
+        T sampled = stream.get(this.x + x, this.z + z);
+        data[index] = sampled;
+        return sampled;
     }
 }

core/src/main/java/art/arcane/iris/util/project/interpolation/IrisInterpolation.java

@@ -37,6 +37,7 @@ import java.util.HashMap;
 public class IrisInterpolation {
     public static CNG cng = NoiseStyle.SIMPLEX.create(new RNG());
     private static final ThreadLocal<NoiseSampleCache2D> NOISE_SAMPLE_CACHE_2D = ThreadLocal.withInitial(() -> new NoiseSampleCache2D(64));
+    private static final ThreadLocal<NoiseBoundsSampleCache2D> NOISE_BOUNDS_SAMPLE_CACHE_2D = ThreadLocal.withInitial(() -> new NoiseBoundsSampleCache2D(64));
 
     public static double bezier(double t) {
         return t * t * (3.0d - 2.0d * t);
@@ -1041,6 +1042,16 @@ public class IrisInterpolation {
         return n.noise(x, z);
     }
 
+    public static NoiseBounds getNoiseBounds(InterpolationMethod method, int x, int z, double h, NoiseBoundsProvider noise) {
+        NoiseBoundsSampleCache2D cache = NOISE_BOUNDS_SAMPLE_CACHE_2D.get();
+        cache.clear();
+        NoiseProvider minProvider = (sampleX, sampleZ) -> cache.getOrSampleMin(sampleX, sampleZ, noise);
+        NoiseProvider maxProvider = (sampleX, sampleZ) -> cache.getOrSampleMax(sampleX, sampleZ, noise);
+        double min = getNoise(method, x, z, h, minProvider);
+        double max = getNoise(method, x, z, h, maxProvider);
+        return new NoiseBounds(min, max);
+    }
+
     private static boolean usesSampleCache(InterpolationMethod method) {
         return switch (method) {
             case BILINEAR_STARCAST_3,
@@ -1176,6 +1187,170 @@ public class IrisInterpolation {
         }
     }
 
+    @FunctionalInterface
+    public interface NoiseBoundsProvider {
+        NoiseBounds noise(double x, double z);
+    }
+
+    public static final class NoiseBounds {
+        private final double min;
+        private final double max;
+
+        public NoiseBounds(double min, double max) {
+            this.min = min;
+            this.max = max;
+        }
+
+        public double min() {
+            return min;
+        }
+
+        public double max() {
+            return max;
+        }
+    }
+
+    private static class NoiseBoundsSampleCache2D {
+        private long[] xBits;
+        private long[] zBits;
+        private double[] minValues;
+        private double[] maxValues;
+        private byte[] states;
+        private int mask;
+        private int resizeThreshold;
+        private int size;
+
+        public NoiseBoundsSampleCache2D(int initialCapacity) {
+            int minimumCapacity = Math.max(8, initialCapacity);
+            int tableSize = tableSizeFor((minimumCapacity << 1) + minimumCapacity);
+            xBits = new long[tableSize];
+            zBits = new long[tableSize];
+            minValues = new double[tableSize];
+            maxValues = new double[tableSize];
+            states = new byte[tableSize];
+            mask = tableSize - 1;
+            resizeThreshold = Math.max(1, (tableSize * 3) >> 2);
+            size = 0;
+        }
+
+        public void clear() {
+            if (size == 0) {
+                return;
+            }
+            Arrays.fill(states, (byte) 0);
+            size = 0;
+        }
+
+        public double getOrSampleMin(double sampleX, double sampleZ, NoiseBoundsProvider provider) {
+            long xBitsValue = Double.doubleToLongBits(sampleX);
+            long zBitsValue = Double.doubleToLongBits(sampleZ);
+            int slot = findSlot(xBitsValue, zBitsValue);
+            if (states[slot] != 0) {
+                return minValues[slot];
+            }
+
+            NoiseBounds bounds = provider.noise(sampleX, sampleZ);
+            insert(slot, xBitsValue, zBitsValue, bounds.min(), bounds.max());
+            return bounds.min();
+        }
+
+        public double getOrSampleMax(double sampleX, double sampleZ, NoiseBoundsProvider provider) {
+            long xBitsValue = Double.doubleToLongBits(sampleX);
+            long zBitsValue = Double.doubleToLongBits(sampleZ);
+            int slot = findSlot(xBitsValue, zBitsValue);
+            if (states[slot] != 0) {
+                return maxValues[slot];
+            }
+
+            NoiseBounds bounds = provider.noise(sampleX, sampleZ);
+            insert(slot, xBitsValue, zBitsValue, bounds.min(), bounds.max());
+            return bounds.max();
+        }
+
+        private int findSlot(long xb, long zb) {
+            int slot = mix(xb, zb) & mask;
+            while (states[slot] != 0) {
+                if (xBits[slot] == xb && zBits[slot] == zb) {
+                    break;
+                }
+                slot = (slot + 1) & mask;
+            }
+            return slot;
+        }
+
+        private void insert(int slot, long xb, long zb, double min, double max) {
+            xBits[slot] = xb;
+            zBits[slot] = zb;
+            minValues[slot] = min;
+            maxValues[slot] = max;
+            states[slot] = 1;
+            size++;
+            if (size >= resizeThreshold) {
+                grow();
+            }
+        }
+
+        private int mix(long xb, long zb) {
+            long hash = xb * 0x9E3779B97F4A7C15L;
+            hash ^= Long.rotateLeft(zb * 0xC2B2AE3D27D4EB4FL, 32);
+            hash ^= (hash >>> 33);
+            hash *= 0xff51afd7ed558ccdL;
+            hash ^= (hash >>> 33);
+            return (int) hash;
+        }
+
+        private void grow() {
+            long[] previousXBits = xBits;
+            long[] previousZBits = zBits;
+            double[] previousMin = minValues;
+            double[] previousMax = maxValues;
+            byte[] previousStates = states;
+
+            int nextLength = xBits.length << 1;
+            long[] nextXBits = new long[nextLength];
+            long[] nextZBits = new long[nextLength];
+            double[] nextMin = new double[nextLength];
+            double[] nextMax = new double[nextLength];
+            byte[] nextStates = new byte[nextLength];
+
+            xBits = nextXBits;
+            zBits = nextZBits;
+            minValues = nextMin;
+            maxValues = nextMax;
+            states = nextStates;
+            mask = nextLength - 1;
+            resizeThreshold = Math.max(1, (nextLength * 3) >> 2);
+            size = 0;
+
+            for (int i = 0; i < previousStates.length; i++) {
+                if (previousStates[i] == 0) {
+                    continue;
+                }
+                int slot = findSlot(previousXBits[i], previousZBits[i]);
+                xBits[slot] = previousXBits[i];
+                zBits[slot] = previousZBits[i];
+                minValues[slot] = previousMin[i];
+                maxValues[slot] = previousMax[i];
+                states[slot] = 1;
+                size++;
+            }
+        }
+
+        private int tableSizeFor(int value) {
+            int n = value - 1;
+            n |= n >>> 1;
+            n |= n >>> 2;
+            n |= n >>> 4;
+            n |= n >>> 8;
+            n |= n >>> 16;
+            int tableSize = n + 1;
+            if (tableSize < 8) {
+                return 8;
+            }
+            return tableSize;
+        }
+    }
+
     public static double rangeScale(double amin, double amax, double bmin, double bmax, double b) {
         return amin + ((amax - amin) * ((b - bmin) / (bmax - bmin)));
     }

core/src/main/java/art/arcane/iris/util/project/noise/CNG.java

@@ -63,6 +63,7 @@ public class CNG {
     private FloatCache cache;
     private NoiseGenerator generator;
     private NoiseInjector injector;
+    private InjectorMode injectorMode;
     private RNG rng;
     private boolean noscale;
     private int oct;
@@ -106,6 +107,7 @@ public class CNG {
         this.generator = generator;
         this.opacity = opacity;
         this.injector = ADD;
+        this.injectorMode = InjectorMode.ADD;
 
         if (generator instanceof OctaveNoise) {
             ((OctaveNoise) generator).setOctaves(octaves);
@@ -345,11 +347,60 @@ public class CNG {
     }
 
     public CNG injectWith(NoiseInjector i) {
-        injector = i;
+        injector = i == null ? ADD : i;
+        injectorMode = resolveInjectorMode(injector);
         return this;
     }
 
+    private InjectorMode resolveInjectorMode(NoiseInjector i) {
+        if (i == ADD) {
+            return InjectorMode.ADD;
+        }
+
+        if (i == SRC_SUBTRACT) {
+            return InjectorMode.SRC_SUBTRACT;
+        }
+
+        if (i == DST_SUBTRACT) {
+            return InjectorMode.DST_SUBTRACT;
+        }
+
+        if (i == MULTIPLY) {
+            return InjectorMode.MULTIPLY;
+        }
+
+        if (i == MAX) {
+            return InjectorMode.MAX;
+        }
+
+        if (i == MIN) {
+            return InjectorMode.MIN;
+        }
+
+        if (i == SRC_MOD) {
+            return InjectorMode.SRC_MOD;
+        }
+
+        if (i == SRC_POW) {
+            return InjectorMode.SRC_POW;
+        }
+
+        if (i == DST_MOD) {
+            return InjectorMode.DST_MOD;
+        }
+
+        if (i == DST_POW) {
+            return InjectorMode.DST_POW;
+        }
+
+        return InjectorMode.CUSTOM;
+    }
+
     public <T extends IRare> T fitRarity(KList<T> b, double... dim) {
+        if (dim.length == 2) {
+            return fitRarity2D(b, dim[0], dim[1]);
+        }
+
         if (b.size() == 0) {
             return null;
         }
@@ -358,27 +409,7 @@ public class CNG {
             return b.get(0);
         }
 
-        KList<T> rarityMapped = new KList<>();
-        boolean o = false;
-        int max = 1;
-        for (T i : b) {
-            if (i.getRarity() > max) {
-                max = i.getRarity();
-            }
-        }
-
-        max++;
-
-        for (T i : b) {
-            for (int j = 0; j < max - i.getRarity(); j++) {
-                //noinspection AssignmentUsedAsCondition
-                if (o = !o) {
-                    rarityMapped.add(i);
-                } else {
-                    rarityMapped.add(0, i);
-                }
-            }
-        }
+        KList<T> rarityMapped = buildRarityMapped(b);
 
         if (rarityMapped.size() == 1) {
             return rarityMapped.get(0);
@@ -391,6 +422,92 @@ public class CNG {
         return fit(rarityMapped, dim);
     }
 
+    public <T extends IRare> T fitRarity2D(KList<T> b, double x, double z) {
+        if (b.size() == 0) {
+            return null;
+        }
+
+        if (b.size() == 1) {
+            return b.get(0);
+        }
+
+        KList<T> rarityMapped = buildRarityMapped(b);
+        if (rarityMapped.size() == 1) {
+            return rarityMapped.get(0);
+        }
+
+        if (rarityMapped.isEmpty()) {
+            throw new RuntimeException("BAD RARITY MAP! RELATED TO: " + b.toString(", or possibly "));
+        }
+
+        return fit2D(rarityMapped, x, z);
+    }
+
+    private <T extends IRare> KList<T> buildRarityMapped(KList<T> values) {
+        KList<T> rarityMapped = new KList<>();
+        boolean flip = false;
+        int max = 1;
+        for (T value : values) {
+            if (value.getRarity() > max) {
+                max = value.getRarity();
+            }
+        }
+
+        max++;
+        for (T value : values) {
+            int count = max - value.getRarity();
+            for (int j = 0; j < count; j++) {
+                flip = !flip;
+                if (flip) {
+                    rarityMapped.add(value);
+                } else {
+                    rarityMapped.add(0, value);
+                }
+            }
+        }
+
+        return rarityMapped;
+    }
+
+    public <T> T fit2D(T[] values, double x, double z) {
+        if (values.length == 0) {
+            return null;
+        }
+
+        if (values.length == 1) {
+            return values[0];
+        }
+
+        return values[fit2D(0, values.length - 1, x, z)];
+    }
+
+    public <T> T fit2D(List<T> values, double x, double z) {
+        if (values.isEmpty()) {
+            return null;
+        }
+
+        if (values.size() == 1) {
+            return values.get(0);
+        }
+
+        try {
+            return values.get(fit2D(0, values.size() - 1, x, z));
+        } catch (Throwable e) {
+            Iris.reportError(e);
+        }
+
+        return values.get(0);
+    }
+
+    public int fit2D(int min, int max, double x, double z) {
+        if (min == max) {
+            return min;
+        }
+
+        double noise = noiseFast2D(x, z);
+        return (int) Math.round(IrisInterpolation.lerp(min, max, noise));
+    }
+
     public <T> T fit(T[] v, double... dim) {
         if (v.length == 0) {
             return null;
@@ -432,13 +549,7 @@ public class CNG {
     }
 
     public int fit(int min, int max, double x, double z) {
-        if (min == max) {
-            return min;
-        }
-
-        double noise = noise(x, z);
-
-        return (int) Math.round(IrisInterpolation.lerp(min, max, noise));
+        return fit2D(min, max, x, z);
     }
 
     public int fit(int min, int max, double x, double y, double z) {
@@ -466,7 +577,7 @@ public class CNG {
             return (int) Math.round(min);
         }
 
-        double noise = noise(x, z);
+        double noise = noiseFast2D(x, z);
 
         return (int) Math.round(IrisInterpolation.lerp(min, max, noise));
     }
@@ -610,9 +721,34 @@ public class CNG {
 
         if (children != null) {
             for (CNG i : children) {
-                double[] r = injector.combine(n, i.noise(x));
-                n = r[0];
-                m += r[1];
+                double source = n;
+                double value = i.noise(x);
+                switch (injectorMode) {
+                    case ADD -> {
+                        n = source + value;
+                        m += 1D;
+                    }
+                    case SRC_SUBTRACT -> {
+                        n = source - value < 0D ? 0D : source - value;
+                        m -= 1D;
+                    }
+                    case DST_SUBTRACT -> {
+                        n = value - source < 0D ? 0D : source - value;
+                        m -= 1D;
+                    }
+                    case MULTIPLY -> n = source * value;
+                    case MAX -> n = Math.max(source, value);
+                    case MIN -> n = Math.min(source, value);
+                    case SRC_MOD -> n = source % value;
+                    case SRC_POW -> n = Math.pow(source, value);
+                    case DST_MOD -> n = value % source;
+                    case DST_POW -> n = Math.pow(value, source);
+                    case CUSTOM -> {
+                        double[] combined = injector.combine(source, value);
+                        n = combined[0];
+                        m += combined[1];
+                    }
+                }
             }
         }
 
@@ -626,9 +762,34 @@ public class CNG {
 
         if (children != null) {
             for (CNG i : children) {
-                double[] r = injector.combine(n, i.noise(x, z));
-                n = r[0];
-                m += r[1];
+                double source = n;
+                double value = i.noise(x, z);
+                switch (injectorMode) {
+                    case ADD -> {
+                        n = source + value;
+                        m += 1D;
+                    }
+                    case SRC_SUBTRACT -> {
+                        n = source - value < 0D ? 0D : source - value;
+                        m -= 1D;
+                    }
+                    case DST_SUBTRACT -> {
+                        n = value - source < 0D ? 0D : source - value;
+                        m -= 1D;
+                    }
+                    case MULTIPLY -> n = source * value;
+                    case MAX -> n = Math.max(source, value);
+                    case MIN -> n = Math.min(source, value);
+                    case SRC_MOD -> n = source % value;
+                    case SRC_POW -> n = Math.pow(source, value);
+                    case DST_MOD -> n = value % source;
+                    case DST_POW -> n = Math.pow(value, source);
+                    case CUSTOM -> {
+                        double[] combined = injector.combine(source, value);
+                        n = combined[0];
+                        m += combined[1];
+                    }
+                }
             }
         }
 
@@ -642,9 +803,34 @@ public class CNG {
 
         if (children != null) {
             for (CNG i : children) {
-                double[] r = injector.combine(n, i.noise(x, y, z));
-                n = r[0];
-                m += r[1];
+                double source = n;
+                double value = i.noise(x, y, z);
+                switch (injectorMode) {
+                    case ADD -> {
+                        n = source + value;
+                        m += 1D;
+                    }
+                    case SRC_SUBTRACT -> {
+                        n = source - value < 0D ? 0D : source - value;
+                        m -= 1D;
+                    }
+                    case DST_SUBTRACT -> {
+                        n = value - source < 0D ? 0D : source - value;
+                        m -= 1D;
+                    }
+                    case MULTIPLY -> n = source * value;
+                    case MAX -> n = Math.max(source, value);
+                    case MIN -> n = Math.min(source, value);
+                    case SRC_MOD -> n = source % value;
+                    case SRC_POW -> n = Math.pow(source, value);
+                    case DST_MOD -> n = value % source;
+                    case DST_POW -> n = Math.pow(value, source);
+                    case CUSTOM -> {
+                        double[] combined = injector.combine(source, value);
+                        n = combined[0];
+                        m += combined[1];
+                    }
+                }
             }
         }
 
@@ -673,9 +859,34 @@ public class CNG {
         }
 
         for (CNG i : children) {
-            double[] r = injector.combine(n, i.noise(dim));
-            n = r[0];
-            m += r[1];
+            double source = n;
+            double value = i.noise(dim);
+            switch (injectorMode) {
+                case ADD -> {
+                    n = source + value;
+                    m += 1D;
+                }
+                case SRC_SUBTRACT -> {
+                    n = source - value < 0D ? 0D : source - value;
+                    m -= 1D;
+                }
+                case DST_SUBTRACT -> {
+                    n = value - source < 0D ? 0D : source - value;
+                    m -= 1D;
+                }
+                case MULTIPLY -> n = source * value;
+                case MAX -> n = Math.max(source, value);
+                case MIN -> n = Math.min(source, value);
+                case SRC_MOD -> n = source % value;
+                case SRC_POW -> n = Math.pow(source, value);
+                case DST_MOD -> n = value % source;
+                case DST_POW -> n = Math.pow(value, source);
+                case CUSTOM -> {
+                    double[] combined = injector.combine(source, value);
+                    n = combined[0];
+                    m += combined[1];
+                }
+            }
         }
 
         return ((n / m) - down + up) * patch;
@@ -685,6 +896,10 @@ public class CNG {
         return applyPost(getNoise(x), x);
     }
 
+    public double noiseFast1D(double x) {
+        return applyPost(getNoise(x), x);
+    }
+
     public double noise(double x, double z) {
         if (cache != null && isWholeCoordinate(x) && isWholeCoordinate(z)) {
             return cache.get((int) x, (int) z);
@@ -693,10 +908,22 @@ public class CNG {
         return applyPost(getNoise(x, z), x, z);
     }
 
+    public double noiseFast2D(double x, double z) {
+        if (cache != null && isWholeCoordinate(x) && isWholeCoordinate(z)) {
+            return cache.get((int) x, (int) z);
+        }
+
+        return applyPost(getNoise(x, z), x, z);
+    }
+
     public double noise(double x, double y, double z) {
         return applyPost(getNoise(x, y, z), x, y, z);
     }
 
+    public double noiseFast3D(double x, double y, double z) {
+        return applyPost(getNoise(x, y, z), x, y, z);
+    }
+
     public CNG pow(double power) {
         this.power = power;
         return this;
@@ -714,4 +941,18 @@ public class CNG {
     public boolean isStatic() {
         return generator != null && generator.isStatic();
     }
+
+    private enum InjectorMode {
+        ADD,
+        SRC_SUBTRACT,
+        DST_SUBTRACT,
+        MULTIPLY,
+        MAX,
+        MIN,
+        SRC_MOD,
+        SRC_POW,
+        DST_MOD,
+        DST_POW,
+        CUSTOM
+    }
 }

core/src/main/java/art/arcane/iris/util/project/stream/utility/CachedStream2D.java

@@ -53,7 +53,6 @@ public class CachedStream2D<T> extends BasicStream<T> implements ProceduralStrea
 
     @Override
     public T get(double x, double z) {
-        //return stream.get(x, z);
         return cache.get((int) x, (int) z);
     }
 
@@ -81,4 +80,10 @@ public class CachedStream2D<T> extends BasicStream<T> implements ProceduralStrea
     public boolean isClosed() {
         return engine.isClosed();
     }
+
+    public void fillChunk(int worldX, int worldZ, Object[] target) {
+        int chunkX = worldX >> 4;
+        int chunkZ = worldZ >> 4;
+        cache.fillChunk(chunkX, chunkZ, target);
+    }
 }

core/src/test/java/art/arcane/iris/core/IrisRuntimeSchedulerModeRoutingTest.java

@@ -0,0 +1,75 @@
+package art.arcane.iris.core;
+
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.Server;
+import org.bukkit.block.data.BlockData;
+import org.junit.Test;
+
+import java.util.logging.Logger;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assume.assumeTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.mockingDetails;
+
+public class IrisRuntimeSchedulerModeRoutingTest {
+    @Test
+    public void autoResolvesToPaperLikeOnPurpurBranding() {
+        installServer("Purpur", "git-Purpur-2562 (MC: 1.21.11)");
+        IrisSettings.IrisSettingsPregen pregen = new IrisSettings.IrisSettingsPregen();
+        pregen.runtimeSchedulerMode = IrisRuntimeSchedulerMode.AUTO;
+
+        IrisRuntimeSchedulerMode resolved = IrisRuntimeSchedulerMode.resolve(pregen);
+        assertEquals(IrisRuntimeSchedulerMode.PAPER_LIKE, resolved);
+    }
+
+    @Test
+    public void autoResolvesToFoliaWhenBrandingContainsFolia() {
+        installServer("Folia", "git-Folia-123 (MC: 1.21.11)");
+        IrisSettings.IrisSettingsPregen pregen = new IrisSettings.IrisSettingsPregen();
+        pregen.runtimeSchedulerMode = IrisRuntimeSchedulerMode.AUTO;
+
+        IrisRuntimeSchedulerMode resolved = IrisRuntimeSchedulerMode.resolve(pregen);
+        assertEquals(IrisRuntimeSchedulerMode.FOLIA, resolved);
+    }
+
+    @Test
+    public void explicitModeBypassesAutoDetection() {
+        installServer("Purpur", "git-Purpur-2562 (MC: 1.21.11)");
+        IrisSettings.IrisSettingsPregen pregen = new IrisSettings.IrisSettingsPregen();
+
+        pregen.runtimeSchedulerMode = IrisRuntimeSchedulerMode.FOLIA;
+        IrisRuntimeSchedulerMode foliaResolved = IrisRuntimeSchedulerMode.resolve(pregen);
+        assertEquals(IrisRuntimeSchedulerMode.PAPER_LIKE, foliaResolved);
+
+        pregen.runtimeSchedulerMode = IrisRuntimeSchedulerMode.PAPER_LIKE;
+        IrisRuntimeSchedulerMode paperResolved = IrisRuntimeSchedulerMode.resolve(pregen);
+        assertEquals(IrisRuntimeSchedulerMode.PAPER_LIKE, paperResolved);
+    }
+
+    private void installServer(String name, String version) {
+        Server server = Bukkit.getServer();
+        if (server == null) {
+            server = mock(Server.class);
+            try {
+                Bukkit.setServer(server);
+            } catch (Throwable ignored) {
+                server = Bukkit.getServer();
+            }
+        }
+
+        assumeTrue(server != null && mockingDetails(server).isMock());
+
+        BlockData emptyBlockData = mock(BlockData.class);
+        doReturn(Logger.getLogger("IrisTest")).when(server).getLogger();
+        doReturn(name).when(server).getName();
+        doReturn(version).when(server).getVersion();
+        doReturn(version).when(server).getBukkitVersion();
+        doReturn(emptyBlockData).when(server).createBlockData(any(Material.class));
+        doReturn(emptyBlockData).when(server).createBlockData(anyString());
+    }
+}

core/src/test/java/art/arcane/iris/engine/IrisComplexImplodeParityTest.java

@@ -0,0 +1,111 @@
+package art.arcane.iris.engine;
+
+import art.arcane.iris.engine.object.IrisBiome;
+import art.arcane.iris.util.project.noise.CNG;
+import art.arcane.volmlib.util.collection.KList;
+import art.arcane.volmlib.util.math.RNG;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.Server;
+import org.bukkit.block.data.BlockData;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+
+public class IrisComplexImplodeParityTest {
+    private static Method childSelectionCreateMethod;
+    private static Method childSelectionSelectMethod;
+
+    @BeforeClass
+    public static void setup() throws Exception {
+        if (Bukkit.getServer() == null) {
+            Server server = mock(Server.class);
+            BlockData emptyBlockData = mock(BlockData.class);
+            doReturn(Logger.getLogger("IrisTest")).when(server).getLogger();
+            doReturn("IrisTestServer").when(server).getName();
+            doReturn("1.0").when(server).getVersion();
+            doReturn("1.0").when(server).getBukkitVersion();
+            doReturn(emptyBlockData).when(server).createBlockData(any(Material.class));
+            doReturn(emptyBlockData).when(server).createBlockData(anyString());
+            Bukkit.setServer(server);
+        }
+
+        Class<?> childSelectionClass = Class.forName("art.arcane.iris.engine.IrisComplex$ChildSelectionPlan");
+        childSelectionCreateMethod = childSelectionClass.getDeclaredMethod("create", KList.class);
+        childSelectionCreateMethod.setAccessible(true);
+        childSelectionSelectMethod = childSelectionClass.getDeclaredMethod("select", CNG.class, double.class, double.class);
+        childSelectionSelectMethod.setAccessible(true);
+    }
+
+    @Test
+    public void selectionPlanMatchesLegacyFitRarityAcrossSeedAndCoordinateGrid() throws Exception {
+        List<KList<IrisBiome>> scenarios = buildScenarios();
+        for (int scenarioIndex = 0; scenarioIndex < scenarios.size(); scenarioIndex++) {
+            KList<IrisBiome> options = scenarios.get(scenarioIndex);
+            Object selectionPlan = childSelectionCreateMethod.invoke(null, options);
+            for (long seed = 1L; seed <= 7L; seed++) {
+                CNG generator = new CNG(new RNG(seed), 4);
+                for (int x = -512; x <= 512; x += 37) {
+                    for (int z = -512; z <= 512; z += 41) {
+                        IrisBiome expected = generator.fitRarity(options, x, z);
+                        IrisBiome actual = (IrisBiome) childSelectionSelectMethod.invoke(selectionPlan, generator, (double) x, (double) z);
+                        assertSame("scenario=" + scenarioIndex + " seed=" + seed + " x=" + x + " z=" + z, expected, actual);
+                    }
+                }
+            }
+        }
+    }
+
+    @Test
+    public void emptySelectionPlanMatchesLegacyEmptyBehavior() throws Exception {
+        KList<IrisBiome> options = new KList<>();
+        CNG generator = new CNG(new RNG(9L), 2);
+        Object selectionPlan = childSelectionCreateMethod.invoke(null, options);
+        IrisBiome expected = generator.fitRarity(options, 12D, -32D);
+        IrisBiome actual = (IrisBiome) childSelectionSelectMethod.invoke(selectionPlan, generator, 12D, -32D);
+        assertNull(expected);
+        assertNull(actual);
+    }
+
+    private List<KList<IrisBiome>> buildScenarios() {
+        List<KList<IrisBiome>> scenarios = new ArrayList<>();
+
+        KList<IrisBiome> scenarioA = new KList<>();
+        scenarioA.add(createBiome(1));
+        scenarioA.add(createBiome(3));
+        scenarioA.add(createBiome(5));
+        scenarioA.add(createBiome(2));
+        scenarios.add(scenarioA);
+
+        KList<IrisBiome> scenarioB = new KList<>();
+        scenarioB.add(createBiome(7));
+        scenarioB.add(createBiome(2));
+        scenarioB.add(createBiome(2));
+        scenarioB.add(createBiome(6));
+        scenarioB.add(createBiome(1));
+        scenarios.add(scenarioB);
+
+        KList<IrisBiome> scenarioC = new KList<>();
+        scenarioC.add(createBiome(4));
+        scenarios.add(scenarioC);
+
+        return scenarios;
+    }
+
+    private IrisBiome createBiome(int rarity) {
+        IrisBiome biome = mock(IrisBiome.class);
+        doReturn(rarity).when(biome).getRarity();
+        return biome;
+    }
+}

core/src/test/java/art/arcane/iris/engine/object/IrisDimensionCarvingResolverParityTest.java

@@ -57,8 +57,8 @@ public class IrisDimensionCarvingResolverParityTest {
             IrisDimensionCarvingEntry statefulRoot = IrisDimensionCarvingResolver.resolveRootEntry(fixture.engine, worldY, state);
             assertSame("root mismatch at worldY=" + worldY, legacyRoot, statefulRoot);
 
-            for (int worldX = -192; worldX <= 192; worldX += 31) {
-                for (int worldZ = -192; worldZ <= 192; worldZ += 37) {
+            for (int worldX = -384; worldX <= 384; worldX += 29) {
+                for (int worldZ = -384; worldZ <= 384; worldZ += 31) {
                     IrisDimensionCarvingEntry legacyResolved = legacyResolveFromRoot(fixture.engine, legacyRoot, worldX, worldZ);
                     IrisDimensionCarvingEntry statefulResolved = IrisDimensionCarvingResolver.resolveFromRoot(fixture.engine, statefulRoot, worldX, worldZ, state);
                     assertSame("entry mismatch at worldY=" + worldY + " worldX=" + worldX + " worldZ=" + worldZ, legacyResolved, statefulResolved);
@@ -67,6 +67,26 @@ public class IrisDimensionCarvingResolverParityTest {
         }
     }
 
+    @Test
+    public void resolverStatefulOverloadsMatchLegacyResolverAcrossMixedDepthGraph() {
+        Fixture fixture = createMixedDepthFixture();
+        IrisDimensionCarvingResolver.State state = new IrisDimensionCarvingResolver.State();
+
+        for (int worldY = -64; worldY <= 320; worldY += 17) {
+            IrisDimensionCarvingEntry legacyRoot = legacyResolveRootEntry(fixture.engine, worldY);
+            IrisDimensionCarvingEntry statefulRoot = IrisDimensionCarvingResolver.resolveRootEntry(fixture.engine, worldY, state);
+            assertSame("mixed root mismatch at worldY=" + worldY, legacyRoot, statefulRoot);
+
+            for (int worldX = -640; worldX <= 640; worldX += 79) {
+                for (int worldZ = -640; worldZ <= 640; worldZ += 83) {
+                    IrisDimensionCarvingEntry legacyResolved = legacyResolveFromRoot(fixture.engine, legacyRoot, worldX, worldZ);
+                    IrisDimensionCarvingEntry statefulResolved = IrisDimensionCarvingResolver.resolveFromRoot(fixture.engine, statefulRoot, worldX, worldZ, state);
+                    assertSame("mixed entry mismatch at worldY=" + worldY + " worldX=" + worldX + " worldZ=" + worldZ, legacyResolved, statefulResolved);
+                }
+            }
+        }
+    }
+
     @Test
     public void caveBiomeStateOverloadMatchesDefaultOverloadAcrossSampleGrid() {
         Fixture fixture = createFixture();
@@ -145,6 +165,92 @@ public class IrisDimensionCarvingResolverParityTest {
         return new Fixture(engine);
     }
 
+    private Fixture createMixedDepthFixture() {
+        IrisBiome rootLowBiome = mock(IrisBiome.class);
+        IrisBiome rootHighBiome = mock(IrisBiome.class);
+        IrisBiome childABiome = mock(IrisBiome.class);
+        IrisBiome childBBiome = mock(IrisBiome.class);
+        IrisBiome childCBiome = mock(IrisBiome.class);
+        IrisBiome childDBiome = mock(IrisBiome.class);
+        IrisBiome childEBiome = mock(IrisBiome.class);
+        IrisBiome childFBiome = mock(IrisBiome.class);
+        IrisBiome childGBiome = mock(IrisBiome.class);
+        IrisBiome fallbackBiome = mock(IrisBiome.class);
+        IrisBiome surfaceBiome = mock(IrisBiome.class);
+
+        doReturn(7).when(rootLowBiome).getRarity();
+        doReturn(5).when(rootHighBiome).getRarity();
+        doReturn(2).when(childABiome).getRarity();
+        doReturn(3).when(childBBiome).getRarity();
+        doReturn(6).when(childCBiome).getRarity();
+        doReturn(1).when(childDBiome).getRarity();
+        doReturn(4).when(childEBiome).getRarity();
+        doReturn(8).when(childFBiome).getRarity();
+        doReturn(2).when(childGBiome).getRarity();
+        doReturn(0).when(fallbackBiome).getCaveMinDepthBelowSurface();
+
+        @SuppressWarnings("unchecked")
+        ResourceLoader<IrisBiome> biomeLoader = mock(ResourceLoader.class);
+        doReturn(rootLowBiome).when(biomeLoader).load("root-low");
+        doReturn(rootHighBiome).when(biomeLoader).load("root-high");
+        doReturn(childABiome).when(biomeLoader).load("child-a");
+        doReturn(childBBiome).when(biomeLoader).load("child-b");
+        doReturn(childCBiome).when(biomeLoader).load("child-c");
+        doReturn(childDBiome).when(biomeLoader).load("child-d");
+        doReturn(childEBiome).when(biomeLoader).load("child-e");
+        doReturn(childFBiome).when(biomeLoader).load("child-f");
+        doReturn(childGBiome).when(biomeLoader).load("child-g");
+
+        IrisData data = mock(IrisData.class);
+        doReturn(biomeLoader).when(data).getBiomeLoader();
+
+        IrisDimensionCarvingEntry rootLow = buildEntry("root-low", "root-low", new IrisRange(-64, 120), 7, List.of("child-a", "child-d", "child-e"));
+        IrisDimensionCarvingEntry rootHigh = buildEntry("root-high", "root-high", new IrisRange(121, 320), 6, List.of("child-b", "child-c", "child-f"));
+        IrisDimensionCarvingEntry childA = buildEntry("child-a", "child-a", new IrisRange(-4096, 4096), 5, List.of("child-b", "child-g"));
+        IrisDimensionCarvingEntry childB = buildEntry("child-b", "child-b", new IrisRange(-4096, 4096), 1, List.of("child-c"));
+        IrisDimensionCarvingEntry childC = buildEntry("child-c", "child-c", new IrisRange(-4096, 4096), 0, List.of());
+        IrisDimensionCarvingEntry childD = buildEntry("child-d", "child-d", new IrisRange(-4096, 4096), 6, List.of("child-e", "child-f"));
+        IrisDimensionCarvingEntry childE = buildEntry("child-e", "child-e", new IrisRange(-4096, 4096), 2, List.of("child-a"));
+        IrisDimensionCarvingEntry childF = buildEntry("child-f", "child-f", new IrisRange(-4096, 4096), 8, List.of("child-g", "child-c"));
+        IrisDimensionCarvingEntry childG = buildEntry("child-g", "child-g", new IrisRange(-4096, 4096), 3, List.of("child-d"));
+
+        KList<IrisDimensionCarvingEntry> carvingEntries = new KList<>();
+        carvingEntries.add(rootLow);
+        carvingEntries.add(rootHigh);
+        carvingEntries.add(childA);
+        carvingEntries.add(childB);
+        carvingEntries.add(childC);
+        carvingEntries.add(childD);
+        carvingEntries.add(childE);
+        carvingEntries.add(childF);
+        carvingEntries.add(childG);
+
+        Map<String, IrisDimensionCarvingEntry> index = new HashMap<>();
+        index.put(rootLow.getId(), rootLow);
+        index.put(rootHigh.getId(), rootHigh);
+        index.put(childA.getId(), childA);
+        index.put(childB.getId(), childB);
+        index.put(childC.getId(), childC);
+        index.put(childD.getId(), childD);
+        index.put(childE.getId(), childE);
+        index.put(childF.getId(), childF);
+        index.put(childG.getId(), childG);
+
+        IrisDimension dimension = mock(IrisDimension.class);
+        doReturn(carvingEntries).when(dimension).getCarving();
+        doReturn(index).when(dimension).getCarvingEntryIndex();
+
+        Engine engine = mock(Engine.class, CALLS_REAL_METHODS);
+        doReturn(dimension).when(engine).getDimension();
+        doReturn(data).when(engine).getData();
+        doReturn(new SeedManager(4_627_991_643L)).when(engine).getSeedManager();
+        doReturn(IrisWorld.builder().minHeight(-64).maxHeight(320).build()).when(engine).getWorld();
+        doReturn(surfaceBiome).when(engine).getSurfaceBiome(anyInt(), anyInt());
+        doReturn(fallbackBiome).when(engine).getCaveBiome(anyInt(), anyInt());
+
+        return new Fixture(engine);
+    }
+
     private IrisDimensionCarvingEntry buildEntry(String id, String biome, IrisRange worldRange, int depth, List<String> children) {
         IrisDimensionCarvingEntry entry = new IrisDimensionCarvingEntry();
         entry.setId(id);

core/src/test/java/art/arcane/iris/util/project/noise/CNGInjectorParityTest.java

@@ -0,0 +1,208 @@
+package art.arcane.iris.util.project.noise;
+
+import art.arcane.volmlib.util.function.NoiseInjector;
+import art.arcane.volmlib.util.math.RNG;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.Server;
+import org.bukkit.block.data.BlockData;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+
+public class CNGInjectorParityTest {
+    @BeforeClass
+    public static void setupBukkit() {
+        if (Bukkit.getServer() != null) {
+            return;
+        }
+
+        Server server = mock(Server.class);
+        BlockData emptyBlockData = mock(BlockData.class);
+        doReturn(Logger.getLogger("IrisTest")).when(server).getLogger();
+        doReturn("IrisTestServer").when(server).getName();
+        doReturn("1.0").when(server).getVersion();
+        doReturn("1.0").when(server).getBukkitVersion();
+        doReturn(emptyBlockData).when(server).createBlockData(any(Material.class));
+        doReturn(emptyBlockData).when(server).createBlockData(anyString());
+        Bukkit.setServer(server);
+    }
+
+    @Test
+    public void builtInInjectorsMatchLegacyCombineFor1D() {
+        List<NoiseInjector> injectors = builtInInjectors();
+        for (NoiseInjector injector : injectors) {
+            CompositeFixture fixture = createFixture(injector);
+            for (int x = -300; x <= 300; x += 17) {
+                double expected = legacyCombined1D(fixture, x);
+                double actual = fixture.root.noise(x);
+                assertEquals("injector=" + injector + " x=" + x, expected, actual, 1.0E-12D);
+            }
+        }
+    }
+
+    @Test
+    public void builtInInjectorsMatchLegacyCombineFor2D() {
+        List<NoiseInjector> injectors = builtInInjectors();
+        for (NoiseInjector injector : injectors) {
+            CompositeFixture fixture = createFixture(injector);
+            for (int x = -160; x <= 160; x += 19) {
+                for (int z = -160; z <= 160; z += 23) {
+                    double expected = legacyCombined2D(fixture, x, z);
+                    double actual = fixture.root.noise(x, z);
+                    assertEquals("injector=" + injector + " x=" + x + " z=" + z, expected, actual, 1.0E-12D);
+                }
+            }
+        }
+    }
+
+    @Test
+    public void builtInInjectorsMatchLegacyCombineFor3D() {
+        List<NoiseInjector> injectors = builtInInjectors();
+        for (NoiseInjector injector : injectors) {
+            CompositeFixture fixture = createFixture(injector);
+            for (int x = -64; x <= 64; x += 11) {
+                for (int y = -32; y <= 32; y += 13) {
+                    for (int z = -64; z <= 64; z += 17) {
+                        double expected = legacyCombined3D(fixture, x, y, z);
+                        double actual = fixture.root.noise(x, y, z);
+                        assertEquals("injector=" + injector + " x=" + x + " y=" + y + " z=" + z, expected, actual, 1.0E-12D);
+                    }
+                }
+            }
+        }
+    }
+
+    private CompositeFixture createFixture(NoiseInjector injector) {
+        DeterministicNoiseGenerator rootGenerator = new DeterministicNoiseGenerator(0.17D);
+        DeterministicNoiseGenerator childGeneratorA = new DeterministicNoiseGenerator(0.43D);
+        DeterministicNoiseGenerator childGeneratorB = new DeterministicNoiseGenerator(0.79D);
+
+        CNG childA = new CNG(new RNG(11L), childGeneratorA, 1.0D, 1).bake();
+        CNG childB = new CNG(new RNG(12L), childGeneratorB, 1.0D, 1).bake();
+
+        CNG root = new CNG(new RNG(9L), rootGenerator, 1.0D, 1).bake();
+        root.child(childA);
+        root.child(childB);
+        root.injectWith(injector);
+
+        return new CompositeFixture(root, rootGenerator, childA, childB, injector);
+    }
+
+    private List<NoiseInjector> builtInInjectors() {
+        List<NoiseInjector> injectors = new ArrayList<>();
+        injectors.add(CNG.ADD);
+        injectors.add(CNG.SRC_SUBTRACT);
+        injectors.add(CNG.DST_SUBTRACT);
+        injectors.add(CNG.MULTIPLY);
+        injectors.add(CNG.MAX);
+        injectors.add(CNG.MIN);
+        injectors.add(CNG.SRC_MOD);
+        injectors.add(CNG.SRC_POW);
+        injectors.add(CNG.DST_MOD);
+        injectors.add(CNG.DST_POW);
+        return injectors;
+    }
+
+    private double legacyCombined1D(CompositeFixture fixture, double x) {
+        double n = fixture.rootGenerator.noise(x, 0D, 0D);
+        double m = 1D;
+
+        double valueA = fixture.childA.noise(x);
+        double[] combinedA = fixture.injector.combine(n, valueA);
+        n = combinedA[0];
+        m += combinedA[1];
+
+        double valueB = fixture.childB.noise(x);
+        double[] combinedB = fixture.injector.combine(n, valueB);
+        n = combinedB[0];
+        m += combinedB[1];
+
+        return n / m;
+    }
+
+    private double legacyCombined2D(CompositeFixture fixture, double x, double z) {
+        double n = fixture.rootGenerator.noise(x, z, 0D);
+        double m = 1D;
+
+        double valueA = fixture.childA.noise(x, z);
+        double[] combinedA = fixture.injector.combine(n, valueA);
+        n = combinedA[0];
+        m += combinedA[1];
+
+        double valueB = fixture.childB.noise(x, z);
+        double[] combinedB = fixture.injector.combine(n, valueB);
+        n = combinedB[0];
+        m += combinedB[1];
+
+        return n / m;
+    }
+
+    private double legacyCombined3D(CompositeFixture fixture, double x, double y, double z) {
+        double n = fixture.rootGenerator.noise(x, y, z);
+        double m = 1D;
+
+        double valueA = fixture.childA.noise(x, y, z);
+        double[] combinedA = fixture.injector.combine(n, valueA);
+        n = combinedA[0];
+        m += combinedA[1];
+
+        double valueB = fixture.childB.noise(x, y, z);
+        double[] combinedB = fixture.injector.combine(n, valueB);
+        n = combinedB[0];
+        m += combinedB[1];
+
+        return n / m;
+    }
+
+    private static class CompositeFixture {
+        private final CNG root;
+        private final DeterministicNoiseGenerator rootGenerator;
+        private final CNG childA;
+        private final CNG childB;
+        private final NoiseInjector injector;
+
+        private CompositeFixture(CNG root, DeterministicNoiseGenerator rootGenerator, CNG childA, CNG childB, NoiseInjector injector) {
+            this.root = root;
+            this.rootGenerator = rootGenerator;
+            this.childA = childA;
+            this.childB = childB;
+            this.injector = injector;
+        }
+    }
+
+    private static class DeterministicNoiseGenerator implements NoiseGenerator {
+        private final double offset;
+
+        private DeterministicNoiseGenerator(double offset) {
+            this.offset = offset;
+        }
+
+        @Override
+        public double noise(double x) {
+            double angle = (x * 0.013D) + offset;
+            return 0.2D + (((Math.sin(angle) + 1D) * 0.5D) * 0.6D);
+        }
+
+        @Override
+        public double noise(double x, double z) {
+            double angle = (x * 0.011D) + (z * 0.017D) + offset;
+            return 0.2D + (((Math.sin(angle) + 1D) * 0.5D) * 0.6D);
+        }
+
+        @Override
+        public double noise(double x, double y, double z) {
+            double angle = (x * 0.007D) + (y * 0.013D) + (z * 0.019D) + offset;
+            return 0.2D + (((Math.sin(angle) + 1D) * 0.5D) * 0.6D);
+        }
+    }
+}