Paper/patches/server/0312-Optimise-getChunkAt-calls-for-loaded-chunks.patch
Bjarne Koll c5a10665b8
Remove wall-time / unused skip tick protection (#11412)
Spigot still maintains some partial implementation of "tick skipping", a
practice in which the MinecraftServer.currentTick field is updated not
by an increment of one per actual tick, but instead set to
System.currentTimeMillis() / 50. This behaviour means that the tracked
tick may "skip" a tick value in case a previous tick took more than the
expected 50ms.

To compensate for this in important paths, spigot/craftbukkit
implements "wall-time". Instead of incrementing/decrementing ticks on
block entities/entities by one for each call to their tick() method,
they instead increment/decrement important values, like
an ItemEntity's age or pickupDelay, by the difference of
`currentTick - lastTick`, where `lastTick` is the value of
`currentTick` during the last tick() call.

These "fixes" however do not play nicely with minecraft's simulation
distance as entities/block entities implementing the above behaviour
would "catch up" their values when moving from a non-ticking chunk to a
ticking one as their `lastTick` value remains stuck on the last tick in
a ticking chunk and hence lead to a large "catch up" once ticked again.

Paper completely removes the "tick skipping" behaviour (See patch
"Further-improve-server-tick-loop"), making the above precautions
completely unnecessary, which also rids paper of the previous described
incompatibility with non-ticking chunks.
2024-09-19 16:36:07 +02:00

61 lines
2.7 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 25 Jan 2020 17:04:35 -0800
Subject: [PATCH] Optimise getChunkAt calls for loaded chunks
bypass the need to get a player chunk, then get the either,
then unwrap it...
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index a939bad7da9c852827a2d67d9ace5d0df4911a31..1049452baaf0381ffbf15b30da956c2a1994da35 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -179,6 +179,12 @@ public class ServerChunkCache extends ChunkSource {
return this.getChunk(x, z, leastStatus, create);
}, this.mainThreadProcessor).join();
} else {
+ // Paper start - Perf: Optimise getChunkAt calls for loaded chunks
+ LevelChunk ifLoaded = this.getChunkAtIfLoadedMainThread(x, z);
+ if (ifLoaded != null) {
+ return ifLoaded;
+ }
+ // Paper end - Perf: Optimise getChunkAt calls for loaded chunks
ProfilerFiller gameprofilerfiller = this.level.getProfiler();
gameprofilerfiller.incrementCounter("getChunk");
@@ -222,33 +228,7 @@ public class ServerChunkCache extends ChunkSource {
if (Thread.currentThread() != this.mainThread) {
return null;
} else {
- this.level.getProfiler().incrementCounter("getChunkNow");
- long k = ChunkPos.asLong(chunkX, chunkZ);
-
- ChunkAccess ichunkaccess;
-
- for (int l = 0; l < 4; ++l) {
- if (k == this.lastChunkPos[l] && this.lastChunkStatus[l] == ChunkStatus.FULL) {
- ichunkaccess = this.lastChunk[l];
- return ichunkaccess instanceof LevelChunk ? (LevelChunk) ichunkaccess : null;
- }
- }
-
- ChunkHolder playerchunk = this.getVisibleChunkIfPresent(k);
-
- if (playerchunk == null) {
- return null;
- } else {
- ichunkaccess = playerchunk.getChunkIfPresent(ChunkStatus.FULL);
- if (ichunkaccess != null) {
- this.storeInCache(k, ichunkaccess, ChunkStatus.FULL);
- if (ichunkaccess instanceof LevelChunk) {
- return (LevelChunk) ichunkaccess;
- }
- }
-
- return null;
- }
+ return this.getChunkAtIfLoadedMainThread(chunkX, chunkZ); // Paper - Perf: Optimise getChunkAt calls for loaded chunks
}
}