PaperMC/patches/server/0255-Optimize-MappedRegistry.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 26 Aug 2018 20:49:50 -0400
Subject: [PATCH] Optimize MappedRegistry

Use larger initial sizes to increase bucket capacity on the BiMap

BiMap.get was seen to be using a good bit of CPU time.

diff --git a/src/main/java/net/minecraft/core/MappedRegistry.java b/src/main/java/net/minecraft/core/MappedRegistry.java
index 889c213205738ba637a28895977714df2d025b6d..87ea9b851531ac98a2dce66651f1730c5eb5e7d4 100644
--- a/src/main/java/net/minecraft/core/MappedRegistry.java
+++ b/src/main/java/net/minecraft/core/MappedRegistry.java
@@ -37,7 +37,7 @@ import org.apache.logging.log4j.Logger;
 public class MappedRegistry<T> extends WritableRegistry<T> {
     protected static final Logger LOGGER = LogManager.getLogger();
     private final ObjectList<T> byId = new ObjectArrayList<>(256);
-    private final Object2IntMap<T> toId = new Object2IntOpenCustomHashMap<>(Util.identityStrategy());
+    private final it.unimi.dsi.fastutil.objects.Reference2IntOpenHashMap<T> toId = new it.unimi.dsi.fastutil.objects.Reference2IntOpenHashMap<T>(2048);// Paper - use bigger expected size to reduce collisions and direct intent for FastUtil to be identity map
     private final BiMap<ResourceLocation, T> storage;
     private final BiMap<ResourceKey<T>, T> keyStorage;
     private final Map<T, Lifecycle> lifecycles;
@@ -48,9 +48,9 @@ public class MappedRegistry<T> extends WritableRegistry<T> {
     public MappedRegistry(ResourceKey<? extends Registry<T>> key, Lifecycle lifecycle) {
         super(key, lifecycle);
         this.toId.defaultReturnValue(-1);
-        this.storage = HashBiMap.create();
-        this.keyStorage = HashBiMap.create();
-        this.lifecycles = Maps.newIdentityHashMap();
+        this.storage = HashBiMap.create(2048); // Paper - use bigger expected size to reduce collisions
+        this.keyStorage = HashBiMap.create(2048); // Paper - use bigger expected size to reduce collisions
+        this.lifecycles = new java.util.IdentityHashMap<>(2048); // Paper - use bigger expected size to reduce collisions
         this.elementsLifecycle = lifecycle;
     }