mirrors/papermc
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages 1 Wiki Activity Actions

Remove wall-time / unused skip tick protection (#11412)

Browse source 
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.
This commit is contained in:
Bjarne Koll 2024-09-19 16:36:07 +02:00 • committed by GitHub
parent 5c82955733
commit c5a10665b8
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
794 changed files with 402 additions and 282 deletions
Download patch file Download diff file Expand all files Collapse all files

44
patches/server/0633-Fix-ChunkSnapshot-isSectionEmpty-int-and-optimize-Pa.patch Normal file
View file

@ -0,0 +1,44 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Thu, 9 Dec 2021 00:08:11 -0800
Subject: [PATCH] Fix ChunkSnapshot#isSectionEmpty(int) and optimize
PalettedContainer copying by not using codecs
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftChunk.java b/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
index f1d5c2d423dc015cc7720a4544370895f3cc644b..d6eab2a0fdbafc35efa7ed5b404357391565f4f3 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
@@ -338,14 +338,17 @@ public class CraftChunk implements Chunk {
PalettedContainerRO<Holder<net.minecraft.world.level.biome.Biome>>[] biome = (includeBiome || includeBiomeTempRain) ? new PalettedContainer[cs.length] : null;
Registry<net.minecraft.world.level.biome.Biome> iregistry = this.worldServer.registryAccess().registryOrThrow(Registries.BIOME);
- Codec<PalettedContainerRO<Holder<net.minecraft.world.level.biome.Biome>>> biomeCodec = PalettedContainer.codecRO(iregistry.asHolderIdMap(), iregistry.holderByNameCodec(), PalettedContainer.Strategy.SECTION_BIOMES, iregistry.getHolderOrThrow(Biomes.PLAINS));
for (int i = 0; i < cs.length; i++) {
- CompoundTag data = new CompoundTag();
- data.put("block_states", ChunkSerializer.BLOCK_STATE_CODEC.encodeStart(NbtOps.INSTANCE, cs[i].getStates()).getOrThrow());
- sectionBlockIDs[i] = ChunkSerializer.BLOCK_STATE_CODEC.parse(NbtOps.INSTANCE, data.getCompound("block_states")).getOrThrow(ChunkSerializer.ChunkReadException::new);
- sectionEmpty[i] = cs[i].hasOnlyAir();
+ // Paper start - Fix ChunkSnapshot#isSectionEmpty(int); and remove codec usage
+ sectionEmpty[i] = cs[i].hasOnlyAir(); // fix sectionEmpty array not being filled
+ if (!sectionEmpty[i]) {
+ sectionBlockIDs[i] = cs[i].getStates().copy(); // use copy instead of round tripping with codecs
+ } else {
+ sectionBlockIDs[i] = CraftChunk.emptyBlockIDs; // use cached instance for empty block sections
+ }
+ // Paper end - Fix ChunkSnapshot#isSectionEmpty(int)
LevelLightEngine lightengine = this.worldServer.getLightEngine();
DataLayer skyLightArray = lightengine.getLayerListener(LightLayer.SKY).getDataLayerData(SectionPos.of(this.x, chunk.getSectionYFromSectionIndex(i), this.z)); // SPIGOT-7498: Convert section index
@@ -364,8 +367,7 @@ public class CraftChunk implements Chunk {
}
if (biome != null) {
- data.put("biomes", biomeCodec.encodeStart(NbtOps.INSTANCE, cs[i].getBiomes()).getOrThrow());
- biome[i] = biomeCodec.parse(NbtOps.INSTANCE, data.getCompound("biomes")).getOrThrow(ChunkSerializer.ChunkReadException::new);
+ biome[i] = ((PalettedContainer<Holder<net.minecraft.world.level.biome.Biome>>) cs[i].getBiomes()).copy(); // Paper - Perf: use copy instead of round tripping with codecs
}
}