PaperMC/patches/server/0602-Make-sure-inlined-getChunkAt-has-inlined-logic-for-l.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

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1.7 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 20 Sep 2020 16:10:49 -0700
Subject: [PATCH] Make sure inlined getChunkAt has inlined logic for loaded
chunks
Tux did some profiling some time ago and showed that the
previous getChunkAt method which had inlined logic for loaded
chunks did get inlined, but the standard CPS.getChunkAt
method was not inlined.
diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index 20a14b4163807b806bf2ce5a88d3c35098bed929..b4111bcc6a676dc42b233761aa667708669c2ab8 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -352,7 +352,14 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
@Override
public final LevelChunk getChunk(int chunkX, int chunkZ) { // Paper - final to help inline
- return (LevelChunk) this.getChunk(chunkX, chunkZ, ChunkStatus.FULL, true); // Paper - avoid a method jump
+ // Paper start - Perf: make sure loaded chunks get the inlined variant of this function
+ net.minecraft.server.level.ServerChunkCache cps = ((ServerLevel)this).getChunkSource();
+ LevelChunk ifLoaded = cps.getChunkAtIfLoadedImmediately(chunkX, chunkZ);
+ if (ifLoaded != null) {
+ return ifLoaded;
+ }
+ return (LevelChunk) cps.getChunk(chunkX, chunkZ, ChunkStatus.FULL, true); // Paper - avoid a method jump
+ // Paper end - Perf: make sure loaded chunks get the inlined variant of this function
}
// Paper start - if loaded