isolate io stuff in its own MultiBurst

core/src/main/java/com/volmit/iris/Iris.java

@@ -485,6 +485,7 @@ public class Iris extends VolmitPlugin implements Listener {
                     .forEach(PlatformChunkGenerator::close);
 
             MultiBurst.burst.close();
+            MultiBurst.ioBurst.close();
             services.clear();
         });
         Runtime.getRuntime().addShutdownHook(shutdownHook);

core/src/main/java/com/volmit/iris/core/IrisSettings.java

@@ -49,11 +49,10 @@ public class IrisSettings {
     private IrisSettingsSentry sentry = new IrisSettingsSentry();
 
     public static int getThreadCount(int c) {
-        return switch (c) {
+        return Math.max(switch (c) {
             case -1, -2, -4 -> Runtime.getRuntime().availableProcessors() / -c;
-            case 0, 1, 2 -> 1;
             default -> Math.max(c, 2);
-        };
+        }, 1);
     }
 
     public static IrisSettings get() {
@@ -138,6 +137,7 @@ public class IrisSettings {
     @Data
     public static class IrisSettingsConcurrency {
         public int parallelism = -1;
+        public int ioParallelism = -2;
         public int worldGenParallelism = -1;
 
         public int getWorldGenThreads() {

core/src/main/java/com/volmit/iris/core/loader/IrisData.java

@@ -482,7 +482,7 @@ public class IrisData implements ExclusionStrategy, TypeAdapterFactory {
     }
 
     public void savePrefetch(Engine engine) {
-        BurstExecutor b = MultiBurst.burst.burst(loaders.size());
+        BurstExecutor b = MultiBurst.ioBurst.burst(loaders.size());
 
         for (ResourceLoader<?> i : loaders.values()) {
             b.queue(() -> {
@@ -499,7 +499,7 @@ public class IrisData implements ExclusionStrategy, TypeAdapterFactory {
     }
 
     public void loadPrefetch(Engine engine) {
-        BurstExecutor b = MultiBurst.burst.burst(loaders.size());
+        BurstExecutor b = MultiBurst.ioBurst.burst(loaders.size());
 
         for (ResourceLoader<?> i : loaders.values()) {
             b.queue(() -> {

core/src/main/java/com/volmit/iris/core/loader/ResourceLoader.java

@@ -235,7 +235,7 @@ public class ResourceLoader<T extends IrisRegistrant> implements MeteredCache {
 
     public KList<T> loadAllParallel(KList<String> s) {
         KList<T> m = new KList<>();
-        BurstExecutor burst = MultiBurst.burst.burst(s.size());
+        BurstExecutor burst = MultiBurst.ioBurst.burst(s.size());
 
         for (String i : s) {
             burst.queue(() -> {

core/src/main/java/com/volmit/iris/core/service/PreservationSVC.java

@@ -43,10 +43,6 @@ public class PreservationSVC implements IrisService {
         threads.add(t);
     }
 
-    public void register(MultiBurst burst) {
-
-    }
-
     public void register(ExecutorService service) {
         services.add(service);
     }

core/src/main/java/com/volmit/iris/util/mantle/Mantle.java

@@ -88,7 +88,7 @@ public class Mantle {
         this.ioTectonicUnload = new Semaphore(LOCK_SIZE, true);
         loadedRegions = new KMap<>();
         lastUse = new KMap<>();
-        ioBurst = MultiBurst.burst;
+        ioBurst = MultiBurst.ioBurst;
         adjustedIdleDuration = new AtomicDouble(0);
         toUnload = new KSet<>();
         worker = new IOWorker(dataFolder, worldHeight);

core/src/main/java/com/volmit/iris/util/parallel/MultiBurst.java

@@ -20,7 +20,6 @@ package com.volmit.iris.util.parallel;
 
 import com.volmit.iris.Iris;
 import com.volmit.iris.core.IrisSettings;
-import com.volmit.iris.core.service.PreservationSVC;
 import com.volmit.iris.util.collection.KList;
 import com.volmit.iris.util.math.M;
 import com.volmit.iris.util.scheduling.PrecisionStopwatch;
@@ -30,30 +29,37 @@ import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.IntSupplier;
 
 public class MultiBurst implements ExecutorService {
     private static final long TIMEOUT = Long.getLong("iris.burst.timeout", 15000);
     public static final MultiBurst burst = new MultiBurst();
+    public static final MultiBurst ioBurst = new MultiBurst("Iris IO", () -> IrisSettings.get().getConcurrency().getIoParallelism());
     private final AtomicLong last;
     private final String name;
     private final int priority;
+    private final IntSupplier parallelism;
     private ExecutorService service;
 
     public MultiBurst() {
-        this("Iris", Thread.MIN_PRIORITY);
+        this("Iris", Thread.MIN_PRIORITY, () -> IrisSettings.get().getConcurrency().getParallelism());
     }
 
-    public MultiBurst(String name, int priority) {
+    public MultiBurst(String name, IntSupplier parallelism) {
+        this(name, Thread.MIN_PRIORITY, parallelism);
+    }
+
+    public MultiBurst(String name, int priority, IntSupplier parallelism) {
         this.name = name;
         this.priority = priority;
+        this.parallelism = parallelism;
         last = new AtomicLong(M.ms());
-        Iris.service(PreservationSVC.class).register(this);
     }
 
     private synchronized ExecutorService getService() {
         last.set(M.ms());
         if (service == null || service.isShutdown()) {
-            service = new ForkJoinPool(IrisSettings.getThreadCount(IrisSettings.get().getConcurrency().getParallelism()),
+            service = new ForkJoinPool(IrisSettings.getThreadCount(parallelism.getAsInt()),
                     new ForkJoinPool.ForkJoinWorkerThreadFactory() {
                         int m = 0;