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 30747b30596208bc02dfb4a6c31f8afb5c1aba8e..23af98932a9c1e6dc209a6ce40d52b5bd9ccfcc5 100644
--- a/net/minecraft/server/MinecraftServer.java
+++ b/net/minecraft/server/MinecraftServer.java
@@ -290,6 +290,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
     public static final long SERVER_INIT = System.nanoTime(); // Paper - Lag compensation
     protected boolean upnp = false; // Purpur - UPnP Port Forwarding
     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 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) {
         ca.spottedleaf.dataconverter.minecraft.datatypes.MCTypeRegistry.init(); // Paper - rewrite data converter system
@@ -1674,6 +1675,18 @@ 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) {
+                bukkit.taskScheduler.executeTick();
+            }
+        }
+        /*
         getAllLevels().forEach(level -> {
             for (final net.minecraft.world.entity.Entity entity : level.getEntities().getAll()) {
                 if (entity.isRemoved()) {
@@ -1685,6 +1698,8 @@ 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();