Leaf/patches/server/0005-Pufferfish-Optimize-mob-spawning.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Kevin Raneri <kevin.raneri@gmail.com>
Date: Wed, 10 Nov 2021 00:37:03 -0500
Subject: [PATCH] Pufferfish: Optimize mob spawning

Original license: GPL v3
Original project: https://github.com/pufferfish-gg/Pufferfish

This patch aims to reduce the main-thread impact of mob spawning by
offloading as much work as possible to other threads. It is possible for
inconsistencies to come up, but when they happen they never interfere
with the server's operation (they don't produce errors), and side
effects are limited to more or less mobs being spawned in any particular
tick.

It is possible to disable this optimization if it is not required or if
it interferes with any plugins. On servers with thousands of entities,
this can result in performance gains of up to 15%, which is significant
and, in my opinion, worth the low risk of minor mob-spawning-related
inconsistencies.

diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 3bee751a36c1aaab9b9a738edac80b4d2853bdd7..31b1b1c6a55b04cf1952ddb8ea08da988906ddff 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -297,6 +297,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
     public volatile boolean abnormalExit = false; // Paper
     public boolean isIteratingOverLevels = false; // Paper
 
+    public gg.pufferfish.pufferfish.util.AsyncExecutor mobSpawnExecutor = new gg.pufferfish.pufferfish.util.AsyncExecutor("MobSpawning"); // Pufferfish - optimize mob spawning
     public static <S extends MinecraftServer> S spin(Function<Thread, S> serverFactory) {
         AtomicReference<S> atomicreference = new AtomicReference();
         Thread thread = new io.papermc.paper.util.TickThread(() -> { // Paper - rewrite chunk system
diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
index b94972cfae11a955af14c382d7d679c520bfab13..b66e708b788800ba97c25104770904ffdc460fcc 100644
--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
@@ -350,6 +350,7 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
                 DedicatedServer.LOGGER.info("JMX monitoring enabled");
             }
 
+            if (org.dreeam.leaf.LeafConfig.enableAsyncMobSpawning) mobSpawnExecutor.start(); // Pufferfish
             return true;
         }
     }
diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index be0210aef3805237adb0142d3eb8b4a76a3270e5..bdaf3a157b9f9d8158d8112b0986c80f73b161a7 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -342,7 +342,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         this.dataRegionManager = new io.papermc.paper.chunk.SingleThreadChunkRegionManager(this.level, 2, (1.0 / 3.0), 1, 6, "Data", DataRegionData::new, DataRegionSectionData::new);
         this.regionManagers.add(this.dataRegionManager);
         // Paper end
-        this.playerMobDistanceMap = this.level.paperConfig().entities.spawning.perPlayerMobSpawns ? new com.destroystokyo.paper.util.misc.PlayerAreaMap(this.pooledLinkedPlayerHashSets) : null; // Paper
+        this.playerMobDistanceMap = this.level.paperConfig().entities.spawning.perPlayerMobSpawns ? new gg.pufferfish.pufferfish.util.AsyncPlayerAreaMap(this.pooledLinkedPlayerHashSets) : null; // Paper // Pufferfish
         // Paper start - use distance map to optimise entity tracker
         this.playerEntityTrackerTrackMaps = new com.destroystokyo.paper.util.misc.PlayerAreaMap[TRACKING_RANGE_TYPES.length];
         this.entityTrackerTrackRanges = new int[TRACKING_RANGE_TYPES.length];
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index 075c476cdf02ece97c5e0032726ae1b560825ce1..cb7f88e37b6bd3a0a78f80ef6062e65818ab180c 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -75,6 +75,9 @@ public class ServerChunkCache extends ChunkSource {
     final it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap<LevelChunk> loadedChunkMap = new it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap<>(8192, 0.5f);
 
     private final LevelChunk[] lastLoadedChunks = new LevelChunk[4 * 4];
+    
+    public boolean firstRunSpawnCounts = true; // Pufferfish
+    public final java.util.concurrent.atomic.AtomicBoolean _pufferfish_spawnCountsReady = new java.util.concurrent.atomic.AtomicBoolean(false); // Pufferfish - optimize countmobs
 
     private static int getChunkCacheKey(int x, int z) {
         return x & 3 | ((z & 3) << 2);
@@ -553,6 +556,8 @@ public class ServerChunkCache extends ChunkSource {
             int l = this.distanceManager.getNaturalSpawnChunkCount();
             // Paper start - per player mob spawning
             if ((this.spawnFriendlies || this.spawnEnemies) && this.chunkMap.playerMobDistanceMap != null) { // don't count mobs when animals and monsters are disabled
+            // Pufferfish start - moved down when async processing
+            if (!org.dreeam.leaf.LeafConfig.enableAsyncMobSpawning) {
                 // re-set mob counts
                 for (ServerPlayer player : this.level.players) {
                     // Paper start - per player mob spawning backoff
@@ -567,14 +572,19 @@ public class ServerChunkCache extends ChunkSource {
                     }
                     // Paper end - per player mob spawning backoff
                 }
-                spawnercreature_d = NaturalSpawner.createState(l, this.level.getAllEntities(), this::getFullChunk, null, true);
+                    lastSpawnState = NaturalSpawner.createState(l, this.level.getAllEntities(), this::getFullChunk, null, true);
+                }
+                // Pufferfish end
             } else {
-                spawnercreature_d = NaturalSpawner.createState(l, this.level.getAllEntities(), this::getFullChunk, this.chunkMap.playerMobDistanceMap == null ? new LocalMobCapCalculator(this.chunkMap) : null, false);
+                // Pufferfish start - this is only implemented for per-player mob spawning so this makes everything work if this setting is disabled.
+                lastSpawnState = NaturalSpawner.createState(l, this.level.getAllEntities(), this::getFullChunk, this.chunkMap.playerMobDistanceMap == null ? new LocalMobCapCalculator(this.chunkMap) : null, false);
+                _pufferfish_spawnCountsReady.set(true);
+                // Pufferfish end
             }
             // Paper end
             this.level.timings.countNaturalMobs.stopTiming(); // Paper - timings
 
-            this.lastSpawnState = spawnercreature_d;
+            //this.lastSpawnState = spawnercreature_d; // Pufferfish - this is managed asynchronously
                 // Gale start - MultiPaper - skip unnecessary mob spawning computations
             } else {
                 spawnercreature_d = null;
@@ -614,8 +624,8 @@ public class ServerChunkCache extends ChunkSource {
 
                 if ((true || this.level.isNaturalSpawningAllowed(chunkcoordintpair)) && this.chunkMap.anyPlayerCloseEnoughForSpawning(holder, chunkcoordintpair, false)) { // Paper - optimise anyPlayerCloseEnoughForSpawning // Paper - the chunk is known ticking
                     chunk1.incrementInhabitedTime(j);
-                    if (flag2AndHasNaturalSpawn && (this.spawnEnemies || this.spawnFriendlies) && this.level.getWorldBorder().isWithinBounds(chunkcoordintpair) && this.chunkMap.anyPlayerCloseEnoughForSpawning(holder, chunkcoordintpair, true)) { // Spigot // Paper - optimise anyPlayerCloseEnoughForSpawning & optimise chunk tick iteration // Gale - MultiPaper - skip unnecessary mob spawning computations
-                        NaturalSpawner.spawnForChunk(this.level, chunk1, spawnercreature_d, this.spawnFriendlies, this.spawnEnemies, flag1);
+                    if (flag2AndHasNaturalSpawn && (!org.dreeam.leaf.LeafConfig.enableAsyncMobSpawning || _pufferfish_spawnCountsReady.get()) && (this.spawnEnemies || this.spawnFriendlies) && this.level.getWorldBorder().isWithinBounds(chunkcoordintpair) && this.chunkMap.anyPlayerCloseEnoughForSpawning(holder, chunkcoordintpair, true)) { // Spigot // Paper - optimise anyPlayerCloseEnoughForSpawning & optimise chunk tick iteration // Gale - MultiPaper - skip unnecessary mob spawning computations
+                        NaturalSpawner.spawnForChunk(this.level, chunk1, lastSpawnState, this.spawnFriendlies, this.spawnEnemies, flag1); // Pufferfish
                     }
 
                     if (true || this.level.shouldTickBlocksAt(chunkcoordintpair.toLong())) { // Paper - the chunk is known ticking
@@ -673,6 +683,39 @@ public class ServerChunkCache extends ChunkSource {
             }
             // Paper end - controlled flush for entity tracker packets
         }
+        // Pufferfish start - optimize mob spawning
+        if (org.dreeam.leaf.LeafConfig.enableAsyncMobSpawning) {
+            for (ServerPlayer player : this.level.players) {
+                // Paper start - per player mob spawning backoff
+                for (int ii = 0; ii < ServerPlayer.MOBCATEGORY_TOTAL_ENUMS; ii++) {
+                    player.mobCounts[ii] = 0;
+
+                    int newBackoff = player.mobBackoffCounts[ii] - 1; // TODO make configurable bleed // TODO use nonlinear algorithm?
+                    if (newBackoff < 0) {
+                        newBackoff = 0;
+                    }
+                    player.mobBackoffCounts[ii] = newBackoff;
+                }
+                // Paper end - per player mob spawning backoff
+            }
+            if (firstRunSpawnCounts) {
+                firstRunSpawnCounts = false;
+                _pufferfish_spawnCountsReady.set(true);
+            }
+            if (chunkMap.playerMobDistanceMap != null && _pufferfish_spawnCountsReady.getAndSet(false)) {
+                net.minecraft.server.MinecraftServer.getServer().mobSpawnExecutor.submit(() -> {
+                    int mapped = distanceManager.getNaturalSpawnChunkCount();
+                    io.papermc.paper.util.maplist.IteratorSafeOrderedReferenceSet.Iterator<Entity> objectiterator =
+                            level.entityTickList.entities.iterator(io.papermc.paper.util.maplist.IteratorSafeOrderedReferenceSet.ITERATOR_FLAG_SEE_ADDITIONS);
+                    gg.pufferfish.pufferfish.util.IterableWrapper<Entity> wrappedIterator =
+                            new gg.pufferfish.pufferfish.util.IterableWrapper<>(objectiterator);
+                    lastSpawnState = NaturalSpawner.createState(mapped, wrappedIterator, this::getFullChunk, null, true);
+                    objectiterator.finishedIterating();
+                    _pufferfish_spawnCountsReady.set(true);
+                });
+            }
+        }
+        // Pufferfish end
     }
 
     // Gale start - MultiPaper - skip unnecessary mob spawning computations
diff --git a/src/main/java/net/minecraft/world/level/entity/EntityTickList.java b/src/main/java/net/minecraft/world/level/entity/EntityTickList.java
index 4cdfc433df67afcd455422e9baf56f167dd712ae..57fcf3910f45ce371ac2e237b277b1034caaac4e 100644
--- a/src/main/java/net/minecraft/world/level/entity/EntityTickList.java
+++ b/src/main/java/net/minecraft/world/level/entity/EntityTickList.java
@@ -8,7 +8,7 @@ import javax.annotation.Nullable;
 import net.minecraft.world.entity.Entity;
 
 public class EntityTickList {
-    private final io.papermc.paper.util.maplist.IteratorSafeOrderedReferenceSet<Entity> entities = new io.papermc.paper.util.maplist.IteratorSafeOrderedReferenceSet<>(true); // Paper - rewrite this, always keep this updated - why would we EVER tick an entity that's not ticking?
+    public final io.papermc.paper.util.maplist.IteratorSafeOrderedReferenceSet<Entity> entities = new io.papermc.paper.util.maplist.IteratorSafeOrderedReferenceSet<>(true); // Paper - rewrite this, always keep this updated - why would we EVER tick an entity that's not ticking? // Pufferfish - private->public
 
     private void ensureActiveIsNotIterated() {
         // Paper - replace with better logic, do not delay removals
diff --git a/src/main/java/org/dreeam/leaf/LeafConfig.java b/src/main/java/org/dreeam/leaf/LeafConfig.java
index b1fcd3588c22143f9852805a6cea3b6cf6c33a1f..5d161351e7517acf57e98203bab8c9f9ab9d4005 100644
--- a/src/main/java/org/dreeam/leaf/LeafConfig.java
+++ b/src/main/java/org/dreeam/leaf/LeafConfig.java
@@ -163,7 +163,20 @@ public class LeafConfig {
     private static void removal() {
     }
 
+    public static boolean enableAsyncMobSpawning = true;
+    public static boolean asyncMobSpawningInitialized;
     private static void performance() {
+        boolean asyncMobSpawning = getBoolean("performance.enable-async-mob-spawning", enableAsyncMobSpawning,
+                "Whether or not asynchronous mob spawning should be enabled.",
+                "On servers with many entities, this can improve performance by up to 15%. You must have",
+                "paper's per-player-mob-spawns setting set to true for this to work.",
+                "One quick note - this does not actually spawn mobs async (that would be very unsafe).",
+                "This just offloads some expensive calculations that are required for mob spawning.");
+        // This prevents us from changing the value during a reload.
+        if (!asyncMobSpawningInitialized) {
+            asyncMobSpawningInitialized = true;
+            enableAsyncMobSpawning = asyncMobSpawning;
+        }
     }
 
     private static void network() {