papermc/Spigot-Server-Patches/0454-Don-t-run-entity-collision-code-if-not-needed.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Wed, 15 Apr 2020 17:56:07 -0700
Subject: [PATCH] Don't run entity collision code if not needed

Will not run if max entity craming is disabled and
the max collisions per entity is less than or equal to 0

diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index 58e14a10f5424fefd7c2e1ce644e1712e49eea62..22b033b85f34673928f47a65962d2bb6d34e6976 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -2820,10 +2820,16 @@ public abstract class EntityLiving extends Entity {
     protected void doTick() {}
 
     protected void collideNearby() {
+        // Paper - start don't run getEntities if we're not going to use its result
+        int i = this.world.getGameRules().getInt(GameRules.MAX_ENTITY_CRAMMING);
+        if (i <= 0 && world.paperConfig.maxCollisionsPerEntity <= 0) {
+            return;
+        }
+        // Paper - end don't run getEntities if we're not going to use its result
         List<Entity> list = this.world.getEntities(this, this.getBoundingBox(), IEntitySelector.a(this));
 
         if (!list.isEmpty()) {
-            int i = this.world.getGameRules().getInt(GameRules.MAX_ENTITY_CRAMMING);
+            // Paper - move up
             int j;
 
             if (i > 0 && list.size() > i - 1 && this.random.nextInt(4) == 0) {