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Remove wall-time / unused skip tick protection

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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
2024-09-16 23:07:29 +02:00
parent 883f50eb19
commit c8efaa46cb
3 changed files with 55 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
paper-server/patches/sources/net/minecraft/world/entity/monster/Zombie.java.patch
View File

@@ -57,7 +57,7 @@
private boolean canBreakDoors;
private int inWaterTime;
public int conversionTime;
+ private int lastTick = MinecraftServer.currentTick; // CraftBukkit - add field
+ // private int lastTick = MinecraftServer.currentTick; // CraftBukkit - add field // Paper - remove anti tick skipping measures / wall time
+ private boolean shouldBurnInDay = true; // Paper - Add more Zombie API
public Zombie(EntityType<? extends Zombie> type, Level world) {
@@ -115,27 +115,24 @@
}
}
@@ -203,7 +217,10 @@
@@ -203,7 +217,7 @@
public void tick() {
if (!this.level().isClientSide && this.isAlive() && !this.isNoAi()) {
if (this.isUnderWaterConverting()) {
- --this.conversionTime;
+ // CraftBukkit start - Use wall time instead of ticks for conversion
+ int elapsedTicks = MinecraftServer.currentTick - this.lastTick;
+ this.conversionTime -= elapsedTicks;
+ // CraftBukkit end
+ --this.conversionTime; // Paper - remove anti tick skipping measures / wall time
if (this.conversionTime < 0) {
this.doUnderWaterConversion();
}
@@ -220,6 +237,7 @@
@@ -220,6 +234,7 @@
}
super.tick();
+ this.lastTick = MinecraftServer.currentTick; // CraftBukkit
+ // this.lastTick = MinecraftServer.currentTick; // CraftBukkit // Paper - remove anti tick skipping measures / wall time
}
@Override
@@ -253,7 +271,14 @@
@@ -253,7 +268,14 @@
super.aiStep();
}
@@ -146,11 +143,11 @@
+ }
+ // Paper end - Add more Zombie API
public void startUnderWaterConversion(int ticksUntilWaterConversion) {
+ this.lastTick = MinecraftServer.currentTick; // CraftBukkit
+ // this.lastTick = MinecraftServer.currentTick; // CraftBukkit // Paper - remove anti tick skipping measures / wall time
this.conversionTime = ticksUntilWaterConversion;
this.getEntityData().set(Zombie.DATA_DROWNED_CONVERSION_ID, true);
}
@@ -267,32 +292,51 @@
@@ -267,32 +289,51 @@
}
protected void convertToZombieType(EntityType<? extends Zombie> entityType) {
@@ -215,7 +212,7 @@
@Override
public boolean hurtServer(ServerLevel world, DamageSource source, float amount) {
if (!super.hurtServer(world, source, amount)) {
@@ -323,10 +367,10 @@
@@ -323,10 +364,10 @@
if (SpawnPlacements.isSpawnPositionOk(entitytypes, world, blockposition) && SpawnPlacements.checkSpawnRules(entitytypes, world, EntitySpawnReason.REINFORCEMENT, blockposition, world.random)) {
entityzombie.setPos((double) i1, (double) j1, (double) k1);
@@ -229,7 +226,7 @@
AttributeInstance attributemodifiable = this.getAttribute(Attributes.SPAWN_REINFORCEMENTS_CHANCE);
AttributeModifier attributemodifier = attributemodifiable.getModifier(Zombie.REINFORCEMENT_CALLER_CHARGE_ID);
double d0 = attributemodifier != null ? attributemodifier.amount() : 0.0D;
@@ -352,7 +396,14 @@
@@ -352,7 +393,14 @@
float f = this.level().getCurrentDifficultyAt(this.blockPosition()).getEffectiveDifficulty();
if (this.getMainHandItem().isEmpty() && this.isOnFire() && this.random.nextFloat() < f * 0.3F) {
@@ -245,7 +242,7 @@
}
}
@@ -385,7 +436,7 @@
@@ -385,7 +433,7 @@
@Override
public EntityType<? extends Zombie> getType() {
@@ -254,7 +251,7 @@
}
protected boolean canSpawnInLiquids() {
@@ -414,6 +465,7 @@
@@ -414,6 +462,7 @@
nbt.putBoolean("CanBreakDoors", this.canBreakDoors());
nbt.putInt("InWaterTime", this.isInWater() ? this.inWaterTime : -1);
nbt.putInt("DrownedConversionTime", this.isUnderWaterConverting() ? this.conversionTime : -1);
@@ -262,7 +259,7 @@
}
@Override
@@ -425,6 +477,11 @@
@@ -425,6 +474,11 @@
if (nbt.contains("DrownedConversionTime", 99) && nbt.getInt("DrownedConversionTime") > -1) {
this.startUnderWaterConversion(nbt.getInt("DrownedConversionTime"));
}
@@ -274,7 +271,7 @@
}
@@ -432,10 +489,8 @@
@@ -432,10 +486,8 @@
public boolean killedEntity(ServerLevel world, LivingEntity other) {
boolean flag = super.killedEntity(world, other);
@@ -287,7 +284,7 @@
if (this.convertVillagerToZombieVillager(world, entityvillager)) {
flag = false;
@@ -468,7 +523,7 @@
@@ -468,7 +520,7 @@
float f = difficulty.getSpecialMultiplier();
if (spawnReason != EntitySpawnReason.CONVERSION) {
@@ -296,7 +293,7 @@
}
if (object == null) {
@@ -496,7 +551,7 @@
@@ -496,7 +548,7 @@
entitychicken1.finalizeSpawn(world, difficulty, EntitySpawnReason.JOCKEY, (SpawnGroupData) null);
entitychicken1.setChickenJockey(true);
this.startRiding(entitychicken1);