perf: consolidate level update notifications

Author: ishland

c2me-base/src/main/java/com/ishland/c2me/base/common/scheduler/SchedulingManager.java

@@ -6,6 +6,8 @@
 import net.minecraft.server.world.ChunkLevels;
 import net.minecraft.util.math.ChunkPos;
 
+import java.util.ArrayDeque;
+import java.util.Queue;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.Executor;
@@ -30,6 +32,9 @@ protected void rehash(int newN) {
     private final int id = COUNTER.getAndIncrement();
     private volatile ChunkPos currentSyncLoad = null;
 
+    private boolean consolidatingLevelUpdates = false;
+    private Queue<Runnable> consolidatedLevelUpdates = new ArrayDeque<>();
+
     private final Executor executor;
 
     {
@@ -80,21 +85,52 @@ public Executor positionedExecutor(long pos) {
 
     public void updatePriorityFromLevel(long pos, int level) {
         this.executor.execute(() -> {
-            if (this.getPriorityFromMap(pos) == level) return;
-            final long stamp = this.prioritiesLock.writeLock();
-            try {
-                if (level < MAX_LEVEL) {
-                    this.prioritiesFromLevel.put(pos, level);
-                } else {
-                    this.prioritiesFromLevel.remove(pos);
-                }
-            } finally {
-                this.prioritiesLock.unlockWrite(stamp);
-            }
-            updatePriorityInternal(pos);
+            updatePriorityFromLevel0(pos, level);
         });
     }
 
+    private void updatePriorityFromLevel0(long pos, int level) {
+        if (this.getPriorityFromMap(pos) == level) return;
+        final long stamp = this.prioritiesLock.writeLock();
+        try {
+            if (level < MAX_LEVEL) {
+                this.prioritiesFromLevel.put(pos, level);
+            } else {
+                this.prioritiesFromLevel.remove(pos);
+            }
+        } finally {
+            this.prioritiesLock.unlockWrite(stamp);
+        }
+        updatePriorityInternal(pos);
+    }
+
+    public void updatePriorityFromLevelOnMain(long pos, int level) {
+        if (this.consolidatingLevelUpdates) {
+            this.consolidatedLevelUpdates.add(() -> updatePriorityFromLevel0(pos, level));
+        } else {
+            updatePriorityFromLevel(pos, level);
+        }
+    }
+
+    public void setConsolidatingLevelUpdates(boolean value) {
+        this.consolidatingLevelUpdates = value;
+        if (!value) {
+            if (!this.consolidatedLevelUpdates.isEmpty()) {
+                Queue<Runnable> runnables = this.consolidatedLevelUpdates;
+                this.consolidatedLevelUpdates = new ArrayDeque<>();
+                this.executor.execute(() -> {
+                    for (Runnable runnable : runnables) {
+                        try {
+                            runnable.run();
+                        } catch (Throwable t) {
+                            t.printStackTrace();
+                        }
+                    }
+                });
+            }
+        }
+    }
+
     private void updatePriorityInternal(long pos) {
         final int priority = getPriority(pos);
         final FreeableTaskList locks = this.pos2Tasks.get(pos);

c2me-base/src/main/java/com/ishland/c2me/base/mixin/scheduler/MixinServerChunkManager.java

@@ -0,0 +1,31 @@
+package com.ishland.c2me.base.mixin.scheduler;
+
+import com.ishland.c2me.base.common.scheduler.IVanillaChunkManager;
+import com.ishland.c2me.base.common.scheduler.SchedulingManager;
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+import net.minecraft.server.world.ChunkLevelManager;
+import net.minecraft.server.world.ServerChunkLoadingManager;
+import net.minecraft.server.world.ServerChunkManager;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+
+@Mixin(ServerChunkManager.class)
+public class MixinServerChunkManager {
+
+    @Shadow @Final public ServerChunkLoadingManager chunkLoadingManager;
+
+    @WrapOperation(method = "updateChunks", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/world/ChunkLevelManager;update(Lnet/minecraft/server/world/ServerChunkLoadingManager;)Z"))
+    private boolean consolidatePriorityUpdates(ChunkLevelManager instance, ServerChunkLoadingManager chunkLoadingManager, Operation<Boolean> original) {
+        SchedulingManager schedulingManager = ((IVanillaChunkManager) this.chunkLoadingManager).c2me$getSchedulingManager();
+        schedulingManager.setConsolidatingLevelUpdates(true);
+        try {
+            return original.call(instance, chunkLoadingManager);
+        } finally {
+            schedulingManager.setConsolidatingLevelUpdates(false);
+        }
+    }
+
+}

c2me-base/src/main/java/com/ishland/c2me/base/mixin/scheduler/MixinThreadedAnvilChunkStorage.java

@@ -22,7 +22,7 @@ public class MixinThreadedAnvilChunkStorage implements IVanillaChunkManager {
 
     @Inject(method = "setLevel", at = @At("RETURN"))
     private void onUpdateLevel(long pos, int level, ChunkHolder holder, int i, CallbackInfoReturnable<ChunkHolder> cir) {
-        this.c2me$schedulingManager.updatePriorityFromLevel(pos, level);
+        this.c2me$schedulingManager.updatePriorityFromLevelOnMain(pos, level);
     }
 
 }

c2me-base/src/main/resources/c2me-base.mixins.json

@@ -58,6 +58,7 @@
     "access.fapi.IArrayBackedEvent",
     "instrumentation.MixinServerChunkManager",
     "report.MixinDedicatedServerWatchdog",
+    "scheduler.MixinServerChunkManager",
     "scheduler.MixinThreadedAnvilChunkStorage",
     "theinterface.MixinStorageIoWorker",
     "util.log4j2shutdownhookisnomore.MixinMain",