From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <spottedleaf@spottedleaf.dev>
Date: Mon, 6 Apr 2020 04:20:44 -0700
Subject: [PATCH] Execute chunk tasks mid-tick
This will help the server load chunks if tick times are high.
diff --git a/src/main/java/co/aikar/timings/MinecraftTimings.java b/src/main/java/co/aikar/timings/MinecraftTimings.java
index b27021a42cbed3f0648a8d0903d00d03922ae221..eada966d7f108a6081be7a848f5c1dfcb1eed676 100644
--- a/src/main/java/co/aikar/timings/MinecraftTimings.java
+++ b/src/main/java/co/aikar/timings/MinecraftTimings.java
@@ -45,6 +45,8 @@ public final class MinecraftTimings {
public static final Timing antiXrayUpdateTimer = Timings.ofSafe("anti-xray - update");
public static final Timing antiXrayObfuscateTimer = Timings.ofSafe("anti-xray - obfuscate");
+ public static final Timing midTickChunkTasks = Timings.ofSafe("Mid Tick Chunk Tasks");
+
private static final Map<Class<?>, String> taskNameCache = new MapMaker().weakKeys().makeMap();
private MinecraftTimings() {}
diff --git a/src/main/java/com/destroystokyo/paper/server/ticklist/PaperTickList.java b/src/main/java/com/destroystokyo/paper/server/ticklist/PaperTickList.java
index 5fdaefc128956581be4bb9b34199fd6410563991..b7edc1121797bc1c57e25f540ed0124fa8b36b7a 100644
--- a/src/main/java/com/destroystokyo/paper/server/ticklist/PaperTickList.java
+++ b/src/main/java/com/destroystokyo/paper/server/ticklist/PaperTickList.java
@@ -312,6 +312,7 @@ public final class PaperTickList<T> extends ServerTickList<T> { // extend to avo
toTick.tickState = STATE_SCHEDULED;
this.addToNotTickingReady(toTick);
}
+ MinecraftServer.getServer().executeMidTickTasks(); // Paper - exec chunk tasks during world tick
} catch (final Throwable thr) {
// start copy from TickListServer // TODO check on update
CrashReport crashreport = CrashReport.forThrowable(thr, "Exception while ticking");
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 154b0dd9bcfefbd7e7eae8c2f28bbabcd0fde531..099db3a627c1d3c08f3b923bb02a1cb8a0a268ab 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -330,6 +330,76 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
return s0;
}
+ // Paper start - execute chunk tasks mid tick
+ static final long CHUNK_TASK_QUEUE_BACKOFF_MIN_TIME = 25L * 1000L; // 25us
+ static final long MAX_CHUNK_EXEC_TIME = 1000L; // 1us
+
+ static final long TASK_EXECUTION_FAILURE_BACKOFF = 5L * 1000L; // 5us
+
+ private static long lastMidTickExecute;
+ private static long lastMidTickExecuteFailure;
+
+ private boolean tickMidTickTasks() {
+ // give all worlds a fair chance at by targetting them all.
+ // if we execute too many tasks, that's fine - we have logic to correctly handle overuse of allocated time.
+ boolean executed = false;
+ for (ServerLevel world : this.getAllLevels()) {
+ long currTime = System.nanoTime();
+ if (currTime - world.lastMidTickExecuteFailure <= TASK_EXECUTION_FAILURE_BACKOFF) {
+ continue;
+ }
+ if (!world.getChunkSource().pollTask()) {
+ // we need to back off if this fails
+ world.lastMidTickExecuteFailure = currTime;
+ } else {
+ executed = true;
+ }
+ }
+
+ return executed;
+ }
+
+ public final void executeMidTickTasks() {
+ org.spigotmc.AsyncCatcher.catchOp("mid tick chunk task execution");
+ long startTime = System.nanoTime();
+ if ((startTime - lastMidTickExecute) <= CHUNK_TASK_QUEUE_BACKOFF_MIN_TIME || (startTime - lastMidTickExecuteFailure) <= TASK_EXECUTION_FAILURE_BACKOFF) {
+ // it's shown to be bad to constantly hit the queue (chunk loads slow to a crawl), even if no tasks are executed.
+ // so, backoff to prevent this
+ return;
+ }
+
+ co.aikar.timings.MinecraftTimings.midTickChunkTasks.startTiming();
+ try {
+ for (;;) {
+ boolean moreTasks = this.tickMidTickTasks();
+ long currTime = System.nanoTime();
+ long diff = currTime - startTime;
+
+ if (!moreTasks || diff >= MAX_CHUNK_EXEC_TIME) {
+ if (!moreTasks) {
+ lastMidTickExecuteFailure = currTime;
+ }
+
+ // note: negative values reduce the time
+ long overuse = diff - MAX_CHUNK_EXEC_TIME;
+ if (overuse >= (10L * 1000L * 1000L)) { // 10ms
+ // make sure something like a GC or dumb plugin doesn't screw us over...
+ overuse = 10L * 1000L * 1000L; // 10ms
+ }
+
+ double overuseCount = (double)overuse/(double)MAX_CHUNK_EXEC_TIME;
+ long extraSleep = (long)Math.round(overuseCount*CHUNK_TASK_QUEUE_BACKOFF_MIN_TIME);
+
+ lastMidTickExecute = currTime + extraSleep;
+ return;
+ }
+ }
+ } finally {
+ co.aikar.timings.MinecraftTimings.midTickChunkTasks.stopTiming();
+ }
+ }
+ // Paper end - execute chunk tasks mid tick
+
public MinecraftServer(OptionSet options, DataPackConfig datapackconfiguration, Thread thread, RegistryAccess.RegistryHolder iregistrycustom_dimension, LevelStorageSource.LevelStorageAccess convertable_conversionsession, WorldData savedata, PackRepository resourcepackrepository, Proxy proxy, DataFixer datafixer, ServerResources datapackresources, @Nullable MinecraftSessionService minecraftsessionservice, @Nullable GameProfileRepository gameprofilerepository, @Nullable GameProfileCache usercache, ChunkProgressListenerFactory worldloadlistenerfactory) {
super("Server");
SERVER = this; // Paper - better singleton
@@ -1324,6 +1394,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
private boolean pollTaskInternal() {
if (super.pollTask()) {
+ this.executeMidTickTasks(); // Paper - execute chunk tasks mid tick
return true;
} else {
if (this.haveTime()) {
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index 7ea86cbeb72f08d751c14006f428fe5921916061..108f2212f8bd00247bf73ff4f3ba42830abad459 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -1022,6 +1022,7 @@ public class ServerChunkCache extends ChunkSource {
Collections.shuffle(shuffled);
iterator = shuffled.iterator();
}
+ int chunksTicked = 0; // Paper
try { while (iterator.hasNext()) {
LevelChunk chunk = iterator.next();
ChunkHolder playerchunk = chunk.playerChunk;
@@ -1044,6 +1045,7 @@ public class ServerChunkCache extends ChunkSource {
this.level.tickChunk(chunk, k);
// this.level.timings.doTickTiles.stopTiming(); // Spigot // Paper
}
+ if ((chunksTicked++ & 1) == 0) net.minecraft.server.MinecraftServer.getServer().executeMidTickTasks(); // Paper
}
} // Paper start - optimise chunk tick iteration
} finally {
diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index 7fd55f26ad278aae27c102638ad8ab6776f27c7d..12b13945702a03132d1b4c42864c8036d1357020 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -190,7 +190,9 @@ public class ServerLevel extends Level implements WorldGenLevel {
final Int2ObjectMap<EnderDragonPart> dragonParts;
private final StructureFeatureManager structureFeatureManager;
private final boolean tickTime;
-
+ // Paper start - execute chunk tasks mid tick
+ public long lastMidTickExecuteFailure;
+ // Paper end - execute chunk tasks mid tick
// CraftBukkit start
private int tickPosition;
diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index 82da0f2226f71a5081e24c17a8a39be22e3c5316..6ca0134c76adc335bb5125831e332fd709f09de7 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -912,6 +912,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
public <T extends Entity> void guardEntityTick(Consumer<T> tickConsumer, T entity) {
try {
tickConsumer.accept(entity);
+ MinecraftServer.getServer().executeMidTickTasks(); // Paper - execute chunk tasks mid tick
} catch (Throwable throwable) {
if (throwable instanceof ThreadDeath) throw throwable; // Paper
// Paper start - Prevent tile entity and entity crashes