From c5a10665b8b80af650500b9263036f778f06d500 Mon Sep 17 00:00:00 2001 From: Bjarne Koll Date: Thu, 19 Sep 2024 16:36:07 +0200 Subject: 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. --- patches/server/0335-Optimize-Pathfinding.patch | 47 ++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 patches/server/0335-Optimize-Pathfinding.patch (limited to 'patches/server/0335-Optimize-Pathfinding.patch') diff --git a/patches/server/0335-Optimize-Pathfinding.patch b/patches/server/0335-Optimize-Pathfinding.patch new file mode 100644 index 0000000000..281988ce37 --- /dev/null +++ b/patches/server/0335-Optimize-Pathfinding.patch @@ -0,0 +1,47 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: Aikar +Date: Thu, 3 Mar 2016 02:02:07 -0600 +Subject: [PATCH] Optimize Pathfinding + +Prevents pathfinding from spamming failures for things such as +arrow attacks. + +diff --git a/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java b/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java +index 188904c9f0f81db1d63eec953d6746f2dc23dc81..2e9991e6b3c05584002744a2ee2579b1dba218b2 100644 +--- a/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java ++++ b/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java +@@ -192,13 +192,33 @@ public abstract class PathNavigation { + return this.moveTo(this.createPath(x, y, z, 1), speed); + } + ++ // Paper start - Perf: Optimise pathfinding ++ private int lastFailure = 0; ++ private int pathfindFailures = 0; ++ // Paper end - Perf: Optimise pathfinding ++ + public boolean moveTo(double x, double y, double z, int distance, double speed) { + return this.moveTo(this.createPath(x, y, z, distance), speed); + } + + public boolean moveTo(Entity entity, double speed) { ++ // Paper start - Perf: Optimise pathfinding ++ if (this.pathfindFailures > 10 && this.path == null && net.minecraft.server.MinecraftServer.currentTick < this.lastFailure + 40) { ++ return false; ++ } ++ // Paper end - Perf: Optimise pathfinding + Path path = this.createPath(entity, 1); +- return path != null && this.moveTo(path, speed); ++ // Paper start - Perf: Optimise pathfinding ++ if (path != null && this.moveTo(path, speed)) { ++ this.lastFailure = 0; ++ this.pathfindFailures = 0; ++ return true; ++ } else { ++ this.pathfindFailures++; ++ this.lastFailure = net.minecraft.server.MinecraftServer.currentTick; ++ return false; ++ } ++ // Paper end - Perf: Optimise pathfinding + } + + public boolean moveTo(@Nullable Path path, double speed) { -- cgit v1.2.3