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] SparklyPaper: Skip EntityScheduler's executeTick checks if
 there isn't any tasks to be run

Original project: https://github.com/SparklyPower/SparklyPaper

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/net/minecraft/server/MinecraftServer.java b/net/minecraft/server/MinecraftServer.java
index ee07832a92b3f73bd85d13388276cf224743c0ed..2ecda6d2af7721113384c11d4a96a3b3cb082232 100644
--- a/net/minecraft/server/MinecraftServer.java
+++ b/net/minecraft/server/MinecraftServer.java
@@ -289,6 +289,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
     public gg.pufferfish.pufferfish.util.AsyncExecutor mobSpawnExecutor = new gg.pufferfish.pufferfish.util.AsyncExecutor("Leaf Async Mob Spawn Thread"); // Pufferfish - optimize mob spawning // Leaf - Fix Pufferfish and Purpur patches - Unify thread name
     public boolean lagging = false; // Purpur - Lagging threshold
     protected boolean upnp = false; // Purpur - UPnP Port Forwarding
+    public final Set<net.minecraft.world.entity.Entity> 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> threadFunction) {
         AtomicReference<S> atomicReference = new AtomicReference<>();
@@ -1663,6 +1664,22 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
         this.server.getScheduler().mainThreadHeartbeat(); // CraftBukkit
         // Paper start - Folia scheduler API
         ((io.papermc.paper.threadedregions.scheduler.FoliaGlobalRegionScheduler) org.bukkit.Bukkit.getGlobalRegionScheduler()).tick();
+        // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
+        for (final net.minecraft.world.entity.Entity entity : entitiesWithScheduledTasks) {
+            if (entity.isRemoved()) {
+                continue;
+            }
+
+            final org.bukkit.craftbukkit.entity.CraftEntity bukkit = entity.getBukkitEntityRaw();
+            if (bukkit != null) {
+                io.papermc.paper.threadedregions.EntityScheduler scheduler = bukkit.taskScheduler;
+                scheduler.executeTick();
+                if (!scheduler.hasTasks()) {
+                    this.entitiesWithScheduledTasks.remove(entity);
+                }
+            }
+        }
+        /*
         getAllLevels().forEach(level -> {
             for (final net.minecraft.world.entity.Entity entity : level.getEntities().getAll()) {
                 if (entity.isRemoved()) {
@@ -1674,6 +1691,8 @@ 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.getFunctions().tick();