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

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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
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GPG key ID: B5690EEEBB952194
794 changed files with 402 additions and 282 deletions
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81
patches/server/0706-Prevent-entity-loading-causing-async-lookups.patch Normal file
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@ -0,0 +1,81 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
Date: Sun, 6 Mar 2022 11:09:09 -0500
Subject: [PATCH] Prevent entity loading causing async lookups
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 3bb7e0f6a02b9b1726b8c878271d89a9c6d56c12..de483cc77931fcb1d8bb9b1bcfd6606706490fba 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -714,6 +714,7 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
public void baseTick() {
this.level().getProfiler().push("entityBaseTick");
+ if (firstTick && this instanceof net.minecraft.world.entity.NeutralMob neutralMob) neutralMob.tickInitialPersistentAnger(level); // Paper - Prevent entity loading causing async lookups
this.inBlockState = null;
if (this.isPassenger() && this.getVehicle().isRemoved()) {
this.stopRiding();
diff --git a/src/main/java/net/minecraft/world/entity/NeutralMob.java b/src/main/java/net/minecraft/world/entity/NeutralMob.java
index 3b08905ddc3c2506779ce0eac1a53a4d89442ddc..b55633bf4e26dc00e27ab28c7739c274e48b74c3 100644
--- a/src/main/java/net/minecraft/world/entity/NeutralMob.java
+++ b/src/main/java/net/minecraft/world/entity/NeutralMob.java
@@ -45,24 +45,11 @@ public interface NeutralMob {
UUID uuid = nbt.getUUID("AngryAt");
this.setPersistentAngerTarget(uuid);
- Entity entity = ((ServerLevel) world).getEntity(uuid);
-
- if (entity != null) {
- if (entity instanceof Mob) {
- Mob entityinsentient = (Mob) entity;
-
- this.setTarget(entityinsentient, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
- this.setLastHurtByMob(entityinsentient);
- }
-
- if (entity instanceof Player) {
- Player entityhuman = (Player) entity;
-
- this.setTarget(entityhuman, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
- this.setLastHurtByPlayer(entityhuman);
- }
-
- }
+ // Paper - Prevent entity loading causing async lookups; Moved diff to separate method
+ // If this entity already survived its first tick, e.g. is loaded and ticked in sync, actively
+ // tick the initial persistent anger.
+ // If not, let the first tick on the baseTick call the method later down the line.
+ if (this instanceof Entity entity && !entity.firstTick) this.tickInitialPersistentAnger(world);
}
}
}
@@ -136,4 +123,28 @@ public interface NeutralMob {
@Nullable
LivingEntity getTarget();
+
+ // Paper start - Prevent entity loading causing async lookups
+ // Update last hurt when ticking
+ default void tickInitialPersistentAnger(Level level) {
+ UUID target = getPersistentAngerTarget();
+ if (target == null) {
+ return;
+ }
+
+ Entity entity = ((ServerLevel) level).getEntity(target);
+
+ if (entity != null) {
+ if (entity instanceof Mob mob) {
+ this.setTarget(mob, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
+ this.setLastHurtByMob(mob);
+ }
+
+ if (entity instanceof Player player) {
+ this.setTarget(player, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
+ this.setLastHurtByPlayer(player);
+ }
+ }
+ }
+ // Paper end - Prevent entity loading causing async lookups
}