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 62484ebf4550b05182f693a3180bbac5d5fd906d..4c7aa86bd115c0a6dd6fc8fe20be5c7c48215ca2 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);
     }
 
@@ -66,6 +68,7 @@ public final class EntityScheduler {
                 throw new IllegalStateException("Already retired");
             }
             this.tickCount = RETIRED_TICK_COUNT;
+            this.server.entitiesWithScheduledTasks.remove(entity); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
         }
 
         final Entity thisEntity = this.entity.getHandleRaw();
@@ -124,6 +127,7 @@ public final class EntityScheduler {
             if (this.tickCount == RETIRED_TICK_COUNT) {
                 return false;
             }
+            this.server.entitiesWithScheduledTasks.add(entity); // 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 +147,13 @@ 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(entity); // 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/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 25367df06a8a6e8b0b3a56652a5fb1c70a15632d..e01297d1269e55f4a4f6c43273d194972529645c 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -308,6 +308,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
     // Paper start - lag compensation
     public static final long SERVER_INIT = System.nanoTime();
     // Paper end - lag compensation
+    public final Set<org.bukkit.craftbukkit.entity.CraftEntity> entitiesWithScheduledTasks = java.util.concurrent.ConcurrentHashMap.newKeySet(); // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run (concurrent because plugins may schedule tasks async)
 
     public static <S extends MinecraftServer> S spin(Function<Thread, S> serverFactory) {
         AtomicReference<S> atomicreference = new AtomicReference();
@@ -1471,6 +1472,15 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
         MinecraftTimings.bukkitSchedulerTimer.stopTiming(); // Spigot // Paper
         // Paper start - Folia scheduler API
         ((io.papermc.paper.threadedregions.scheduler.FoliaGlobalRegionScheduler) Bukkit.getGlobalRegionScheduler()).tick();
+        // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
+        for (final org.bukkit.craftbukkit.entity.CraftEntity craftEntity : entitiesWithScheduledTasks) {
+            Entity entity = craftEntity.getHandleRaw();
+            if (entity.isRemoved()) {
+                continue;
+            }
+            craftEntity.taskScheduler.executeTick();
+        }
+        /*
         getAllLevels().forEach(level -> {
             for (final Entity entity : level.getEntityLookup().getAllCopy()) {
                 if (entity.isRemoved()) {
@@ -1482,6 +1492,8 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
                 }
             }
         });
+        */
+        // SparklyPaper end
         // Paper end - Folia scheduler API
         io.papermc.paper.adventure.providers.ClickCallbackProviderImpl.CALLBACK_MANAGER.handleQueue(this.tickCount); // Paper
         this.profiler.push("commandFunctions");
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 9f843b89dc20b91bf7243facee8486d525e4a1b3..d118989be2171c51af6f09e758538b2af476872f 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -208,7 +208,7 @@ 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
@@ -221,6 +221,7 @@ 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 CraftEntity getEntity(CraftServer server, Entity entity) {