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, and due to the thread checks.

To avoid the hefty ArrayDeque's size() call, we check if we *really* need to execute the executeTick, by checking if currentlyExecuting is not empty or if oneTimeDelayed is not empty.

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..1ee31db28d3a4b9b841efeb37f7df7932dfad2dc 100644
--- a/src/main/java/io/papermc/paper/threadedregions/EntityScheduler.java
+++ b/src/main/java/io/papermc/paper/threadedregions/EntityScheduler.java
@@ -138,15 +138,27 @@ public final class EntityScheduler {
      * @throws IllegalStateException If the scheduler is retired.
      */
     public void executeTick() {
+        // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
+        // This wouldn't work on a multithreaded environment like Folia!!! But because the executeTick is always executed on the
+        // main thread, we don't need to care about concurrency
+        if (this.tickCount == RETIRED_TICK_COUNT) {
+            throw new IllegalStateException("Ticking retired scheduler");
+        }
+        ++this.tickCount;
+        if (this.currentlyExecuting.isEmpty() && this.oneTimeDelayed.isEmpty()) // Check if we have any pending tasks and, if not, skip!
+            return;
+        // SparklyPaper end
         final Entity thisEntity = this.entity.getHandleRaw();
 
         TickThread.ensureTickThread(thisEntity, "May not tick entity scheduler asynchronously");
         final List<ScheduledTask> toRun;
         synchronized (this.stateLock) {
-            if (this.tickCount == RETIRED_TICK_COUNT) {
-                throw new IllegalStateException("Ticking retired scheduler");
-            }
-            ++this.tickCount;
+            // SparklyPaper - skip EntityScheduler's executeTick checks if there isn't any tasks to be run
+            // if (this.tickCount == RETIRED_TICK_COUNT) {
+            //     throw new IllegalStateException("Ticking retired scheduler");
+            // }
+            // ++this.tickCount;
+            // SparklyPaper end
             if (this.oneTimeDelayed.isEmpty()) {
                 toRun = null;
             } else {