PaperMC/patches/server/0730-Oprimise-map-impl-for-tracked-players.patch
Spottedleaf 01a13871de
Rewrite chunk system (#8177)
Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.
2022-09-26 01:02:51 -07:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Fri, 19 Feb 2021 22:51:52 -0800
Subject: [PATCH] Oprimise map impl for tracked players
Reference2BooleanOpenHashMap is going to have
better lookups than HashMap.
diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index 3540ac6f99d724d91ff4e897f7e84ef03037f1bf..57b45ce5feaa5015b5468a0b44f354e96d7d95fc 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -1363,7 +1363,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
final Entity entity;
private final int range;
SectionPos lastSectionPos;
- public final Set<ServerPlayerConnection> seenBy = Sets.newIdentityHashSet();
+ public final Set<ServerPlayerConnection> seenBy = new ReferenceOpenHashSet<>(); // Paper - optimise map impl
public TrackedEntity(Entity entity, int i, int j, boolean flag) {
this.serverEntity = new ServerEntity(ChunkMap.this.level, entity, j, flag, this::broadcast, this.seenBy); // CraftBukkit