Add new tick region scheduler

The old region scheduler had a few problems: 1. Inability to process intermediate tasks (chunk/packets) leading to higher than Paper/Vanilla latencies for task processing 2. Thread swapping: scheduled tasks had no thread preference, which lead to them swapping threads which may not be cache efficient The new scheduler solves both of these issues. The new scheduler can process intermediate tasks, and combined with the new packet scheduler this allows packets to be processed at low latency provided that the scheduler threads are idle or waiting. The new scheduler will only move a scheduled tick/task to another scheduling thread provided that its scheduled start is missed by a specified time (for now, 2ms). This should ensure that thread swapping only occurs to meet scheduling deadlines.
2025-04-19 02:29:21 +08:00 · 2025-03-20 11:28:02 -07:00
2 changed files with 2218 additions and 0 deletions
--- a/folia-server/minecraft-patches/features/0009-fixup-Region-Threading-Base.patch
+++ b/folia-server/minecraft-patches/features/0009-fixup-Region-Threading-Base.patch
--- a/folia-server/paper-patches/features/0008-fixup-Region-Threading-Base.patch
+++ b/folia-server/paper-patches/features/0008-fixup-Region-Threading-Base.patch
@ -0,0 +1,71 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <Spottedleaf@users.noreply.github.com>
+Date: Thu, 20 Mar 2025 11:01:42 -0700
+Subject: [PATCH] fixup! Region Threading Base
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+index 6c2d9c9621f665412f1a8ccc41083fb0e3a07ed5..935ac76cec67ea661a392ff02396aa7aefd56268 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+@@ -3125,7 +3125,7 @@ public final class CraftServer implements Server {
+     @Override
+     public double[] getTPS() {
+         // Folia start - region threading
+-        ca.spottedleaf.concurrentutil.scheduler.SchedulerThreadPool.SchedulableTick task = io.papermc.paper.threadedregions.TickRegionScheduler.getCurrentTickingTask();
+        io.papermc.paper.threadedregions.ScheduledTaskThreadPool.SchedulableTick task = io.papermc.paper.threadedregions.TickRegionScheduler.getCurrentTickingTask();
+         if (task == null) {
+             // might be on the shutdown thread, try retrieving the current region
+             if (io.papermc.paper.threadedregions.TickRegionScheduler.getCurrentRegion() != null) {
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index c9afcd46f6a1b74b82ed68f1df6188369cf53a73..d3832c3cf089ee78f542bcc6f0b9c6a760fae9eb 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -227,6 +227,47 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+     private static final boolean DISABLE_CHANNEL_LIMIT = System.getProperty("paper.disableChannelLimit") != null; // Paper - add a flag to disable the channel limit
+     private long lastSaveTime; // Paper - getLastPlayed replacement API
+ 
+    // Folia start - region threading
+    private final ca.spottedleaf.concurrentutil.collection.MultiThreadedQueue<Runnable> packetQueue = new ca.spottedleaf.concurrentutil.collection.MultiThreadedQueue<>();
+    // used only to notify tasks for packets
+    private volatile io.papermc.paper.threadedregions.RegionizedWorldData lastRegion;
+
+    public void stopAcceptingPackets() {
+        this.packetQueue.preventAdds();
+    }
+
+    public void updateRegion(io.papermc.paper.threadedregions.RegionizedWorldData region) {
+        this.lastRegion = region;
+        if (region != null && this.hasPackets()) {
+            region.regionData.setHasPackets();
+        }
+    }
+
+    public boolean hasPackets() {
+        return !this.packetQueue.isEmpty();
+    }
+
+    public boolean executeOnePacket() {
+        final Runnable run = this.packetQueue.poll();
+        if (run != null) {
+            run.run();
+            return true;
+        }
+        return false;
+    }
+
+    public void addPacket(Runnable runnable) {
+        if (!this.packetQueue.add(runnable)) {
+            return;
+        }
+
+        io.papermc.paper.threadedregions.RegionizedWorldData region = this.lastRegion;
+        if (region != null) {
+            region.regionData.setHasPackets();
+        }
+    }
+    // Folia end - region threading
+
+     public CraftPlayer(CraftServer server, ServerPlayer entity) {
+         super(server, entity);
+