PaperMC/patches/server/0413-Use-distance-map-to-optimise-entity-tracker.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Tue, 5 May 2020 20:18:05 -0700
Subject: [PATCH] Use distance map to optimise entity tracker

Use the distance map to find candidate players for tracking.

diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index dadf403ac91887f0fae87889170deb6d5732cbc1..93dea79180ebaef3ffb6abffd47f0026a91406cd 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -157,6 +157,23 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
 
     // Paper start - distance maps
     private final com.destroystokyo.paper.util.misc.PooledLinkedHashSets<ServerPlayer> pooledLinkedPlayerHashSets = new com.destroystokyo.paper.util.misc.PooledLinkedHashSets<>();
+    // Paper start - use distance map to optimise tracker
+    public static boolean isLegacyTrackingEntity(Entity entity) {
+        return entity.isLegacyTrackingEntity;
+    }
+
+    // inlined EnumMap, TrackingRange.TrackingRangeType
+    static final org.spigotmc.TrackingRange.TrackingRangeType[] TRACKING_RANGE_TYPES = org.spigotmc.TrackingRange.TrackingRangeType.values();
+    public final com.destroystokyo.paper.util.misc.PlayerAreaMap[] playerEntityTrackerTrackMaps;
+    final int[] entityTrackerTrackRanges;
+    public final int getEntityTrackerRange(final int ordinal) {
+        return this.entityTrackerTrackRanges[ordinal];
+    }
+
+    private int convertSpigotRangeToVanilla(final int vanilla) {
+        return net.minecraft.server.MinecraftServer.getServer().getScaledTrackingDistance(vanilla);
+    }
+    // Paper end - use distance map to optimise tracker
 
     void addPlayerToDistanceMaps(ServerPlayer player) {
         this.level.playerChunkLoader.addPlayer(player); // Paper - replace chunk loader
@@ -168,6 +185,14 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
             this.playerMobDistanceMap.add(player, chunkX, chunkZ, io.papermc.paper.chunk.system.ChunkSystem.getTickViewDistance(player));
         }
         // Paper end - per player mob spawning
+        // Paper start - use distance map to optimise entity tracker
+        for (int i = 0, len = TRACKING_RANGE_TYPES.length; i < len; ++i) {
+            com.destroystokyo.paper.util.misc.PlayerAreaMap trackMap = this.playerEntityTrackerTrackMaps[i];
+            int trackRange = this.entityTrackerTrackRanges[i];
+
+            trackMap.add(player, chunkX, chunkZ, Math.min(trackRange, io.papermc.paper.chunk.system.ChunkSystem.getSendViewDistance(player)));
+        }
+        // Paper end - use distance map to optimise entity tracker
     }
 
     void removePlayerFromDistanceMaps(ServerPlayer player) {
@@ -178,6 +203,11 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
             this.playerMobDistanceMap.remove(player);
         }
         // Paper end - per player mob spawning
+        // Paper start - use distance map to optimise tracker
+        for (int i = 0, len = TRACKING_RANGE_TYPES.length; i < len; ++i) {
+            this.playerEntityTrackerTrackMaps[i].remove(player);
+        }
+        // Paper end - use distance map to optimise tracker
     }
 
     void updateMaps(ServerPlayer player) {
@@ -190,6 +220,14 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
             this.playerMobDistanceMap.update(player, chunkX, chunkZ, io.papermc.paper.chunk.system.ChunkSystem.getTickViewDistance(player));
         }
         // Paper end - per player mob spawning
+        // Paper start - use distance map to optimise entity tracker
+        for (int i = 0, len = TRACKING_RANGE_TYPES.length; i < len; ++i) {
+            com.destroystokyo.paper.util.misc.PlayerAreaMap trackMap = this.playerEntityTrackerTrackMaps[i];
+            int trackRange = this.entityTrackerTrackRanges[i];
+
+            trackMap.update(player, chunkX, chunkZ, Math.min(trackRange, io.papermc.paper.chunk.system.ChunkSystem.getSendViewDistance(player)));
+        }
+        // Paper end - use distance map to optimise entity tracker
     }
     // Paper end
     // Paper start
@@ -276,6 +314,45 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         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
+        // 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];
+
+        org.spigotmc.SpigotWorldConfig spigotWorldConfig = this.level.spigotConfig;
+
+        for (int ordinal = 0, len = TRACKING_RANGE_TYPES.length; ordinal < len; ++ordinal) {
+            org.spigotmc.TrackingRange.TrackingRangeType trackingRangeType = TRACKING_RANGE_TYPES[ordinal];
+            int configuredSpigotValue;
+            switch (trackingRangeType) {
+                case PLAYER:
+                    configuredSpigotValue = spigotWorldConfig.playerTrackingRange;
+                    break;
+                case ANIMAL:
+                    configuredSpigotValue = spigotWorldConfig.animalTrackingRange;
+                    break;
+                case MONSTER:
+                    configuredSpigotValue = spigotWorldConfig.monsterTrackingRange;
+                    break;
+                case MISC:
+                    configuredSpigotValue = spigotWorldConfig.miscTrackingRange;
+                    break;
+                case OTHER:
+                    configuredSpigotValue = spigotWorldConfig.otherTrackingRange;
+                    break;
+                case ENDERDRAGON:
+                    configuredSpigotValue = EntityType.ENDER_DRAGON.clientTrackingRange() * 16;
+                    break;
+                default:
+                    throw new IllegalStateException("Missing case for enum " + trackingRangeType);
+            }
+            configuredSpigotValue = convertSpigotRangeToVanilla(configuredSpigotValue);
+
+            int trackRange = (configuredSpigotValue >>> 4) + ((configuredSpigotValue & 15) != 0 ? 1 : 0);
+            this.entityTrackerTrackRanges[ordinal] = trackRange;
+
+            this.playerEntityTrackerTrackMaps[ordinal] = new com.destroystokyo.paper.util.misc.PlayerAreaMap(this.pooledLinkedPlayerHashSets);
+        }
+        // Paper end - use distance map to optimise entity tracker
     }
 
     protected ChunkGenerator generator() {
@@ -960,17 +1037,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
     }
 
     public void move(ServerPlayer player) {
-        ObjectIterator objectiterator = this.entityMap.values().iterator();
-
-        while (objectiterator.hasNext()) {
-            ChunkMap.TrackedEntity playerchunkmap_entitytracker = (ChunkMap.TrackedEntity) objectiterator.next();
-
-            if (playerchunkmap_entitytracker.entity == player) {
-                playerchunkmap_entitytracker.updatePlayers(this.level.players());
-            } else {
-                playerchunkmap_entitytracker.updatePlayer(player);
-            }
-        }
+        // Paper - delay this logic for the entity tracker tick, no need to duplicate it
 
         int i = SectionPos.blockToSectionCoord(player.getBlockX());
         int j = SectionPos.blockToSectionCoord(player.getBlockZ());
@@ -1054,7 +1121,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
 
                     entity.tracker = playerchunkmap_entitytracker; // Paper - Fast access to tracker
                     this.entityMap.put(entity.getId(), playerchunkmap_entitytracker);
-                    playerchunkmap_entitytracker.updatePlayers(this.level.players());
+                    playerchunkmap_entitytracker.updatePlayers(entity.getPlayersInTrackRange()); // Paper - don't search all players
                     if (entity instanceof ServerPlayer) {
                         ServerPlayer entityplayer = (ServerPlayer) entity;
 
@@ -1098,7 +1165,37 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         entity.tracker = null; // Paper - We're no longer tracked
     }
 
+    // Paper start - optimised tracker
+    private final void processTrackQueue() {
+        this.level.timings.tracker1.startTiming();
+        try {
+            for (TrackedEntity tracker : this.entityMap.values()) {
+                // update tracker entry
+                tracker.updatePlayers(tracker.entity.getPlayersInTrackRange());
+            }
+        } finally {
+            this.level.timings.tracker1.stopTiming();
+        }
+
+
+        this.level.timings.tracker2.startTiming();
+        try {
+            for (TrackedEntity tracker : this.entityMap.values()) {
+                tracker.serverEntity.sendChanges();
+            }
+        } finally {
+            this.level.timings.tracker2.stopTiming();
+        }
+    }
+    // Paper end - optimised tracker
+
     protected void tick() {
+        // Paper start - optimized tracker
+        if (true) {
+            this.processTrackQueue();
+            return;
+        }
+        // Paper end - optimized tracker
         List<ServerPlayer> list = Lists.newArrayList();
         List<ServerPlayer> list1 = this.level.players();
         ObjectIterator objectiterator = this.entityMap.values().iterator();
@@ -1205,46 +1302,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         }));
         // Paper end
         DebugPackets.sendPoiPacketsForChunk(this.level, chunk.getPos());
-        List<Entity> list = Lists.newArrayList();
-        List<Entity> list1 = Lists.newArrayList();
-        ObjectIterator objectiterator = this.entityMap.values().iterator();
-
-        while (objectiterator.hasNext()) {
-            ChunkMap.TrackedEntity playerchunkmap_entitytracker = (ChunkMap.TrackedEntity) objectiterator.next();
-            Entity entity = playerchunkmap_entitytracker.entity;
-
-            if (entity != player && entity.chunkPosition().equals(chunk.getPos())) {
-                playerchunkmap_entitytracker.updatePlayer(player);
-                if (entity instanceof Mob && ((Mob) entity).getLeashHolder() != null) {
-                    list.add(entity);
-                }
-
-                if (!entity.getPassengers().isEmpty()) {
-                    list1.add(entity);
-                }
-            }
-        }
-
-        Iterator iterator;
-        Entity entity1;
-
-        if (!list.isEmpty()) {
-            iterator = list.iterator();
-
-            while (iterator.hasNext()) {
-                entity1 = (Entity) iterator.next();
-                player.connection.send(new ClientboundSetEntityLinkPacket(entity1, ((Mob) entity1).getLeashHolder()));
-            }
-        }
-
-        if (!list1.isEmpty()) {
-            iterator = list1.iterator();
-
-            while (iterator.hasNext()) {
-                entity1 = (Entity) iterator.next();
-                player.connection.send(new ClientboundSetPassengersPacket(entity1));
-            }
-        }
+        // Paper - no longer needed - this was used to account for clients bugging out since they needed a chunk to store entities, but they no longer need a chunk
 
     }
 
@@ -1299,6 +1357,42 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
             this.lastSectionPos = SectionPos.of((EntityAccess) entity);
         }
 
+        // Paper start - use distance map to optimise tracker
+        com.destroystokyo.paper.util.misc.PooledLinkedHashSets.PooledObjectLinkedOpenHashSet<ServerPlayer> lastTrackerCandidates;
+
+        final void updatePlayers(com.destroystokyo.paper.util.misc.PooledLinkedHashSets.PooledObjectLinkedOpenHashSet<ServerPlayer> newTrackerCandidates) {
+            com.destroystokyo.paper.util.misc.PooledLinkedHashSets.PooledObjectLinkedOpenHashSet<ServerPlayer> oldTrackerCandidates = this.lastTrackerCandidates;
+            this.lastTrackerCandidates = newTrackerCandidates;
+
+            if (newTrackerCandidates != null) {
+                Object[] rawData = newTrackerCandidates.getBackingSet();
+                for (int i = 0, len = rawData.length; i < len; ++i) {
+                    Object raw = rawData[i];
+                    if (!(raw instanceof ServerPlayer)) {
+                        continue;
+                    }
+                    ServerPlayer player = (ServerPlayer)raw;
+                    this.updatePlayer(player);
+                }
+            }
+
+            if (oldTrackerCandidates == newTrackerCandidates) {
+                // this is likely the case.
+                // means there has been no range changes, so we can just use the above for tracking.
+                return;
+            }
+
+            // stuff could have been removed, so we need to check the trackedPlayers set
+            // for players that were removed
+
+            for (ServerPlayerConnection conn : this.seenBy.toArray(new ServerPlayerConnection[0])) { // avoid CME
+                if (newTrackerCandidates == null || !newTrackerCandidates.contains(conn.getPlayer())) {
+                    this.updatePlayer(conn.getPlayer());
+                }
+            }
+        }
+        // Paper end - use distance map to optimise tracker
+
         public boolean equals(Object object) {
             return object instanceof ChunkMap.TrackedEntity ? ((ChunkMap.TrackedEntity) object).entity.getId() == this.entity.getId() : false;
         }
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index f5c1de9671bf823a7f2fa78acfa8f9065d6eb517..c683b5b35ff2bf850283f002c97a28bb6cf223bd 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -57,6 +57,7 @@ import net.minecraft.network.syncher.EntityDataSerializers;
 import net.minecraft.network.syncher.SynchedEntityData;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
+import io.papermc.paper.util.MCUtil;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.server.level.ServerPlayer;
@@ -481,6 +482,38 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
 
     public boolean updatingSectionStatus = false;
     // Paper end
+    // Paper start - optimise entity tracking
+    final org.spigotmc.TrackingRange.TrackingRangeType trackingRangeType = org.spigotmc.TrackingRange.getTrackingRangeType(this);
+
+    public boolean isLegacyTrackingEntity = false;
+
+    public final void setLegacyTrackingEntity(final boolean isLegacyTrackingEntity) {
+        this.isLegacyTrackingEntity = isLegacyTrackingEntity;
+    }
+
+    public final com.destroystokyo.paper.util.misc.PooledLinkedHashSets.PooledObjectLinkedOpenHashSet<ServerPlayer> getPlayersInTrackRange() {
+        // determine highest range of passengers
+        if (this.passengers.isEmpty()) {
+            return ((ServerLevel)this.level).getChunkSource().chunkMap.playerEntityTrackerTrackMaps[this.trackingRangeType.ordinal()]
+                .getObjectsInRange(MCUtil.getCoordinateKey(this));
+        }
+        Iterable<Entity> passengers = this.getIndirectPassengers();
+        net.minecraft.server.level.ChunkMap chunkMap = ((ServerLevel)this.level).getChunkSource().chunkMap;
+        org.spigotmc.TrackingRange.TrackingRangeType type = this.trackingRangeType;
+        int range = chunkMap.getEntityTrackerRange(type.ordinal());
+
+        for (Entity passenger : passengers) {
+            org.spigotmc.TrackingRange.TrackingRangeType passengerType = passenger.trackingRangeType;
+            int passengerRange = chunkMap.getEntityTrackerRange(passengerType.ordinal());
+            if (passengerRange > range) {
+                type = passengerType;
+                range = passengerRange;
+            }
+        }
+
+        return chunkMap.playerEntityTrackerTrackMaps[type.ordinal()].getObjectsInRange(MCUtil.getCoordinateKey(this));
+    }
+    // Paper end - optimise entity tracking
 
     public Entity(EntityType<?> type, Level world) {
         this.id = Entity.ENTITY_COUNTER.incrementAndGet();
diff --git a/src/main/java/org/spigotmc/TrackingRange.java b/src/main/java/org/spigotmc/TrackingRange.java
index 172d231adecf043f9f06b7f5e0365ae82327998d..8fca15099952626ee537f5ce3eefdfaa6518dc1b 100644
--- a/src/main/java/org/spigotmc/TrackingRange.java
+++ b/src/main/java/org/spigotmc/TrackingRange.java
@@ -55,4 +55,45 @@ public class TrackingRange
             return config.otherTrackingRange;
         }
     }
+
+    // Paper start - optimise entity tracking
+    // copied from above, TODO check on update
+    public static TrackingRangeType getTrackingRangeType(Entity entity)
+    {
+        if (entity instanceof net.minecraft.world.entity.boss.enderdragon.EnderDragon) return TrackingRangeType.ENDERDRAGON; // Paper - enderdragon is exempt
+        if ( entity instanceof ServerPlayer )
+        {
+            return TrackingRangeType.PLAYER;
+            // Paper start - Simplify and set water mobs to animal tracking range
+        }
+        switch (entity.activationType) {
+            case RAIDER:
+            case MONSTER:
+            case FLYING_MONSTER:
+                return TrackingRangeType.MONSTER;
+            case WATER:
+            case VILLAGER:
+            case ANIMAL:
+                return TrackingRangeType.ANIMAL;
+            case MISC:
+        }
+        if ( entity instanceof ItemFrame || entity instanceof Painting || entity instanceof ItemEntity || entity instanceof ExperienceOrb )
+        // Paper end
+        {
+            return TrackingRangeType.MISC;
+        } else
+        {
+            return TrackingRangeType.OTHER;
+        }
+    }
+
+    public static enum TrackingRangeType {
+        PLAYER,
+        ANIMAL,
+        MONSTER,
+        MISC,
+        OTHER,
+        ENDERDRAGON;
+    }
+    // Paper end - optimise entity tracking
 }