Leaf/patches/server/0006-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 208b9558d9019cd00f7ed270d2a36f9a28464e65..e2f2bc175d94110e32b412b73528686661b79809 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -310,6 +310,8 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
     public volatile boolean abnormalExit = false; // Paper
     public static final long SERVER_INIT = System.nanoTime(); // Paper - Lag compensation
 
+    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 42ac2efb4c84c5f15c10934f928183962f179626..944ada1e0f4e4a8460ec3c8e1d9a0de7469d395b 100644
--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
@@ -373,6 +373,7 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
                 DedicatedServer.LOGGER.info("JMX monitoring enabled");
             }
 
+            if (org.dreeam.leaf.config.modules.async.AsyncMobSpawning.enabled) mobSpawnExecutor.start(); // Pufferfish
             return true;
         }
     }
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index fe96ee6b36d38a7da61c80715716365d2a33f07d..e59f0957b664c0ae3c4c7ce7d9ab68b038985870 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -128,6 +128,9 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
     }
     // Paper end - rewrite chunk system
 
+    public boolean firstRunSpawnCounts = true; // Pufferfish
+    public final java.util.concurrent.atomic.AtomicBoolean _pufferfish_spawnCountsReady = new java.util.concurrent.atomic.AtomicBoolean(false); // Pufferfish - optimize countmobs
+
     public ServerChunkCache(ServerLevel world, LevelStorageSource.LevelStorageAccess session, DataFixer dataFixer, StructureTemplateManager structureTemplateManager, Executor workerExecutor, ChunkGenerator chunkGenerator, int viewDistance, int simulationDistance, boolean dsync, ChunkProgressListener worldGenerationProgressListener, ChunkStatusUpdateListener chunkStatusChangeListener, Supplier<DimensionDataStorage> persistentStateManagerFactory) {
         this.level = world;
         this.mainThreadProcessor = new ServerChunkCache.MainThreadExecutor(world);
@@ -442,6 +445,7 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
                 // Paper start - Optional per player mob spawns
                 int naturalSpawnChunkCount = k;
                 if ((this.spawnFriendlies || this.spawnEnemies) && this.level.paperConfig().entities.spawning.perPlayerMobSpawns) { // don't count mobs when animals and monsters are disabled
+                    if (!org.dreeam.leaf.config.modules.async.AsyncMobSpawning.enabled) { // Pufferfish - moved down when async processing
                     // re-set mob counts
                     for (ServerPlayer player : this.level.players) {
                         // Paper start - per player mob spawning backoff
@@ -456,14 +460,18 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
                         }
                         // Paper end - per player mob spawning backoff
                     }
-                    spawnercreature_d = NaturalSpawner.createState(naturalSpawnChunkCount, this.level.getAllEntities(), this::getFullChunk, null, true);
+                    lastSpawnState = NaturalSpawner.createState(naturalSpawnChunkCount, this.level.getAllEntities(), this::getFullChunk, null, true); // Pufferfish - async mob spawning
+                    } // Pufferfish - (endif) moved down when async processing
                 } else {
-                    spawnercreature_d = NaturalSpawner.createState(naturalSpawnChunkCount, this.level.getAllEntities(), this::getFullChunk, !this.level.paperConfig().entities.spawning.perPlayerMobSpawns ? new LocalMobCapCalculator(this.chunkMap) : null, false);
+                    // Pufferfish start - async mob spawning
+                    lastSpawnState = NaturalSpawner.createState(naturalSpawnChunkCount, this.level.getAllEntities(), this::getFullChunk, !this.level.paperConfig().entities.spawning.perPlayerMobSpawns ? new LocalMobCapCalculator(this.chunkMap) : null, false);
+                    _pufferfish_spawnCountsReady.set(true);
+                    // Pufferfish end
                 }
                 // Paper end - Optional per player mob spawns
                 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;
@@ -491,8 +499,8 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
 
                     if (this.level.isNaturalSpawningAllowed(chunkcoordintpair) && this.chunkMap.anyPlayerCloseEnoughForSpawning(chunkcoordintpair)) {
                         chunk1.incrementInhabitedTime(j);
-                        if (flagAndHasNaturalSpawn && (this.spawnEnemies || this.spawnFriendlies) && this.level.getWorldBorder().isWithinBounds(chunkcoordintpair) && this.chunkMap.anyPlayerCloseEnoughForSpawning(chunkcoordintpair, true)) { // Spigot // Gale - MultiPaper - skip unnecessary mob spawning computations
-                            NaturalSpawner.spawnForChunk(this.level, chunk1, spawnercreature_d, this.spawnFriendlies, this.spawnEnemies, flag1);
+                        if (flagAndHasNaturalSpawn && (!org.dreeam.leaf.config.modules.async.AsyncMobSpawning.enabled || _pufferfish_spawnCountsReady.get()) && (this.spawnEnemies || this.spawnFriendlies) && this.level.getWorldBorder().isWithinBounds(chunkcoordintpair) && this.chunkMap.anyPlayerCloseEnoughForSpawning(chunkcoordintpair, true)) { // Spigot // Gale - MultiPaper - skip unnecessary mob spawning computations // Pufferfish
+                            NaturalSpawner.spawnForChunk(this.level, chunk1, lastSpawnState, this.spawnFriendlies, this.spawnEnemies, flag1); // Pufferfish
                         }
 
                         if (this.level.shouldTickBlocksAt(chunkcoordintpair.toLong())) {
@@ -520,6 +528,40 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
                 this.level.timings.broadcastChunkUpdates.stopTiming(); // Paper - timing
             });
         }
+
+        // Pufferfish start - optimize mob spawning
+        if (org.dreeam.leaf.config.modules.async.AsyncMobSpawning.enabled) {
+            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 (_pufferfish_spawnCountsReady.getAndSet(false)) {
+                net.minecraft.server.MinecraftServer.getServer().mobSpawnExecutor.submit(() -> {
+                    int mapped = distanceManager.getNaturalSpawnChunkCount();
+                    ca.spottedleaf.moonrise.common.list.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 d8b4196adf955f8d414688dc451caac2d9c609d9..80a43def4912a3228cd95117d5c2aac68798b4ec 100644
--- a/src/main/java/net/minecraft/world/level/entity/EntityTickList.java
+++ b/src/main/java/net/minecraft/world/level/entity/EntityTickList.java
@@ -9,7 +9,7 @@ import javax.annotation.Nullable;
 import net.minecraft.world.entity.Entity;
 
 public class EntityTickList {
-    private final ca.spottedleaf.moonrise.common.list.IteratorSafeOrderedReferenceSet<net.minecraft.world.entity.Entity> entities = new ca.spottedleaf.moonrise.common.list.IteratorSafeOrderedReferenceSet<>(); // Paper - rewrite chunk system
+    public final ca.spottedleaf.moonrise.common.list.IteratorSafeOrderedReferenceSet<net.minecraft.world.entity.Entity> entities = new ca.spottedleaf.moonrise.common.list.IteratorSafeOrderedReferenceSet<>(); // Paper - rewrite chunk system // Pufferfish - private->public
 
     private void ensureActiveIsNotIterated() {
         // Paper - rewrite chunk system
diff --git a/src/main/java/org/dreeam/leaf/config/modules/async/AsyncMobSpawning.java b/src/main/java/org/dreeam/leaf/config/modules/async/AsyncMobSpawning.java
new file mode 100644
index 0000000000000000000000000000000000000000..8a3726a747ff4640f9936a9eae1dca34e5203029
--- /dev/null
+++ b/src/main/java/org/dreeam/leaf/config/modules/async/AsyncMobSpawning.java
@@ -0,0 +1,30 @@
+package org.dreeam.leaf.config.modules.async;
+
+import org.dreeam.leaf.config.ConfigModules;
+import org.dreeam.leaf.config.EnumConfigCategory;
+
+public class AsyncMobSpawning extends ConfigModules {
+
+    public String getBasePath() {
+        return EnumConfigCategory.ASYNC.getBaseKeyName() + ".async-mob-spawning";
+    }
+
+    public static boolean enabled = true;
+    public static boolean asyncMobSpawningInitialized;
+
+    @Override
+    public void onLoaded() {
+        config.addComment(getBasePath(), """
+                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;
+            enabled = config.getBoolean(getBasePath() + ".enabled", enabled);
+        }
+    }
+}