SparklyPaperMC/sparklypaper-server/paper-patches/features/0004-Skip-EntityScheduler-s-executeTick-checks-if-there-i.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: MrPowerGamerBR <git@mrpowergamerbr.com>
Date: Sun, 19 Nov 2023 12:35:16 -0300
Subject: [PATCH] Skip EntityScheduler's executeTick checks if there isn't any
 tasks to be run

On each tick, Paper runs EntityScheduler's executeTick of each entity. This is a bit expensive, due to ArrayDeque's size() call because it ain't a simple "get the current queue size" function, due to the thread checks, and because it needs to iterate all entities in all worlds.

To avoid the hefty ArrayDeque's size() call, we check if we *really* need to execute the executeTick, by adding all entities with scheduled tasks to a global set.

Most entities won't have any scheduled tasks, so this is a nice performance bonus. These optimizations, however, wouldn't work in a Folia environment, but because in SparklyPaper executeTick is always executed on the main thread, it ain't an issue for us (yay).

diff --git a/src/main/java/io/papermc/paper/threadedregions/EntityScheduler.java b/src/main/java/io/papermc/paper/threadedregions/EntityScheduler.java
index c03608fec96b51e1867f43d8f42e5aefb1520e46..15b21fa3907db1b77ed5b5d1050a37f42d27d5ab 100644
--- a/src/main/java/io/papermc/paper/threadedregions/EntityScheduler.java
+++ b/src/main/java/io/papermc/paper/threadedregions/EntityScheduler.java
@@ -36,6 +36,7 @@ public final class EntityScheduler {
      * The Entity. Note that it is the CraftEntity, since only that class properly tracks world transfers.
      */
     public final CraftEntity entity;
+    public final net.minecraft.server.MinecraftServer server; // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
 
     private static final record ScheduledTask(Consumer<? extends Entity> run, Consumer<? extends Entity> retired) {}
 
@@ -46,7 +47,8 @@ public final class EntityScheduler {
 
     private final ArrayDeque<ScheduledTask> currentlyExecuting = new ArrayDeque<>();
 
-    public EntityScheduler(final CraftEntity entity) {
+    public EntityScheduler(final net.minecraft.server.MinecraftServer server, final CraftEntity entity) { // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
+        this.server = Validate.notNull(server);
         this.entity = Validate.notNull(entity);
     }
 
@@ -61,14 +63,16 @@ public final class EntityScheduler {
      * @throws IllegalStateException If the scheduler is already retired.
      */
     public void retire() {
+        final Entity thisEntity = this.entity.getHandleRaw(); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
         synchronized (this.stateLock) {
             if (this.tickCount == RETIRED_TICK_COUNT) {
                 throw new IllegalStateException("Already retired");
             }
             this.tickCount = RETIRED_TICK_COUNT;
+            this.server.entitiesWithScheduledTasks.remove(thisEntity); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
         }
 
-        final Entity thisEntity = this.entity.getHandleRaw();
+        // final Entity thisEntity = this.entity.getHandleRaw(); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run (moved up)
 
         // correctly handle and order retiring while running executeTick
         for (int i = 0, len = this.currentlyExecuting.size(); i < len; ++i) {
@@ -124,6 +128,7 @@ public final class EntityScheduler {
             if (this.tickCount == RETIRED_TICK_COUNT) {
                 return false;
             }
+            this.server.entitiesWithScheduledTasks.add(this.entity.getHandleRaw()); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
             this.oneTimeDelayed.computeIfAbsent(this.tickCount + Math.max(1L, delay), (final long keyInMap) -> {
                 return new ArrayList<>();
             }).add(task);
@@ -143,6 +148,13 @@ public final class EntityScheduler {
         TickThread.ensureTickThread(thisEntity, "May not tick entity scheduler asynchronously");
         final List<ScheduledTask> toRun;
         synchronized (this.stateLock) {
+            // SparklyPaper start - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
+            // Do we *really* have scheduled tasks tho?
+            if (this.currentlyExecuting.isEmpty() && this.oneTimeDelayed.isEmpty()) { // Check if we have any pending tasks and, if not, skip!
+                this.server.entitiesWithScheduledTasks.remove(thisEntity); // We don't! Bye bye!!
+                return;
+            }
+            // SparklyPaper end
             if (this.tickCount == RETIRED_TICK_COUNT) {
                 throw new IllegalStateException("Ticking retired scheduler");
             }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 4562bee2e2795801862bae03d783799fc076b73e..7107acb0a4ad4c84f78185bb8da2db8506c352d1 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -74,7 +74,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
     private final CraftPersistentDataContainer persistentDataContainer = new CraftPersistentDataContainer(CraftEntity.DATA_TYPE_REGISTRY);
     protected net.kyori.adventure.pointer.Pointers adventure$pointers; // Paper - implement pointers
     // Paper start - Folia shedulers
-    public final io.papermc.paper.threadedregions.EntityScheduler taskScheduler = new io.papermc.paper.threadedregions.EntityScheduler(this);
+    public final io.papermc.paper.threadedregions.EntityScheduler taskScheduler; // = new io.papermc.paper.threadedregions.EntityScheduler(this); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
     private final io.papermc.paper.threadedregions.scheduler.FoliaEntityScheduler apiScheduler = new io.papermc.paper.threadedregions.scheduler.FoliaEntityScheduler(this);
 
     @Override
@@ -87,6 +87,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         this.server = server;
         this.entity = entity;
         this.entityType = CraftEntityType.minecraftToBukkit(entity.getType());
+        this.taskScheduler = new io.papermc.paper.threadedregions.EntityScheduler(this.entity.getServer(), this); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
     }
 
     public static <T extends Entity> CraftEntity getEntity(CraftServer server, T entity) {