From 98218db96f2af7763910c2f658da34848d6e2c5c Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 11 Apr 2020 04:40:00 -0400
Subject: [PATCH] Use dedicated thread for main thread blocking chunk loads
In most cases, this change won't benefit much. However, there
exists the possibility that your Chunk Task threads are all busy
doing super slow work such as converting chunks.
If this occurs, the main thread blocking tasks, even at highest priority,
has to wait for some thread to become available.
This change gives us a waiting thread used only for main thread blocking
tasks, as well as an increased thread priority level, so that the OS
will give priority to this thread over the other threads.
This is more about guarantees, and won't be any real performanc boost
to anyone who has low or fast activity on their chunk tasks anyways.
But not all of us force upgrade our worlds, and this can be a life saver.
also reordered some patches because multiple PR's were merged.
---
.../Expose-MinecraftServer-isRunning.patch | 4 +-
.../Add-tick-times-API-and-mspt-command.patch | 8 +-
.../Asynchronous-chunk-IO-and-loading.patch | 104 ++++++++++++++----
.../Expose-MinecraftServer-isRunning.patch | 2 +-
4 files changed, 90 insertions(+), 28 deletions(-)
diff --git a/Spigot-API-Patches/Expose-MinecraftServer-isRunning.patch b/Spigot-API-Patches/Expose-MinecraftServer-isRunning.patch
index d28b983a35..291c03ed85 100644
--- a/Spigot-API-Patches/Expose-MinecraftServer-isRunning.patch
+++ b/Spigot-API-Patches/Expose-MinecraftServer-isRunning.patch
@@ -6,7 +6,7 @@ Subject: [PATCH] Expose MinecraftServer#isRunning
This allows for plugins to detect if the server is actually turning off in onDisable rather than just plugins reloading.
diff --git a/src/main/java/org/bukkit/Bukkit.java b/src/main/java/org/bukkit/Bukkit.java
-index b9973406..dda12412 100644
+index c3c2d9c6b..ea3e5d6fa 100644
--- a/src/main/java/org/bukkit/Bukkit.java
+++ b/src/main/java/org/bukkit/Bukkit.java
@@ -0,0 +0,0 @@ public final class Bukkit {
@@ -26,7 +26,7 @@ index b9973406..dda12412 100644
@NotNull
diff --git a/src/main/java/org/bukkit/Server.java b/src/main/java/org/bukkit/Server.java
-index 80f9abdc..5758ae79 100644
+index bfa83c9bb..9ceaac0e8 100644
--- a/src/main/java/org/bukkit/Server.java
+++ b/src/main/java/org/bukkit/Server.java
@@ -0,0 +0,0 @@ public interface Server extends PluginMessageRecipient {
diff --git a/Spigot-Server-Patches/Add-tick-times-API-and-mspt-command.patch b/Spigot-Server-Patches/Add-tick-times-API-and-mspt-command.patch
index 2f891b7a21..5bf3889605 100644
--- a/Spigot-Server-Patches/Add-tick-times-API-and-mspt-command.patch
+++ b/Spigot-Server-Patches/Add-tick-times-API-and-mspt-command.patch
@@ -6,7 +6,7 @@ Subject: [PATCH] Add tick times API and /mspt command
diff --git a/src/main/java/com/destroystokyo/paper/MSPTCommand.java b/src/main/java/com/destroystokyo/paper/MSPTCommand.java
new file mode 100644
-index 000000000..d0211d4f3
+index 0000000000..d0211d4f39
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/MSPTCommand.java
@@ -0,0 +0,0 @@
@@ -75,7 +75,7 @@ index 000000000..d0211d4f3
+ }
+}
diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
-index 6916ed30c..1c4cd3635 100644
+index 6916ed30c4..1c4cd36351 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -0,0 +0,0 @@ public class PaperConfig {
@@ -87,7 +87,7 @@ index 6916ed30c..1c4cd3635 100644
version = getInt("config-version", 20);
set("config-version", 20);
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
-index c9deaffc4..9e5d569f7 100644
+index 936434110c..2686874f26 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -0,0 +0,0 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
@@ -147,7 +147,7 @@ index c9deaffc4..9e5d569f7 100644
+ // Paper end
}
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
-index b9a398bc5..53b71b791 100644
+index b9a398bc57..53b71b7915 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -0,0 +0,0 @@ public final class CraftServer implements Server {
diff --git a/Spigot-Server-Patches/Asynchronous-chunk-IO-and-loading.patch b/Spigot-Server-Patches/Asynchronous-chunk-IO-and-loading.patch
index fc18c17bc6..ee585f9fd8 100644
--- a/Spigot-Server-Patches/Asynchronous-chunk-IO-and-loading.patch
+++ b/Spigot-Server-Patches/Asynchronous-chunk-IO-and-loading.patch
@@ -1053,7 +1053,7 @@ index 0000000000..4f10a8311e
+}
diff --git a/src/main/java/com/destroystokyo/paper/io/PrioritizedTaskQueue.java b/src/main/java/com/destroystokyo/paper/io/PrioritizedTaskQueue.java
new file mode 100644
-index 0000000000..78bd238f4c
+index 0000000000..97f2e433c4
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/io/PrioritizedTaskQueue.java
@@ -0,0 +0,0 @@
@@ -1131,8 +1131,11 @@ index 0000000000..78bd238f4c
+ * This can also be thrown if the queue has shutdown.
+ */
+ public void add(final T task) throws IllegalStateException {
-+ task.onQueue(this);
-+ this.queues[task.getPriority()].add(task);
++ int priority = task.getPriority();
++ if (priority != COMPLETING_PRIORITY) {
++ task.setQueue(this);
++ this.queues[priority].add(task);
++ }
+ if (this.shutdown.get()) {
+ // note: we're not actually sure at this point if our task will go through
+ throw new IllegalStateException("Queue has shutdown, refusing to execute task " + IOUtil.genericToString(task));
@@ -1309,10 +1312,8 @@ index 0000000000..78bd238f4c
+ }
+ }
+
-+ void onQueue(final PrioritizedTaskQueue queue) {
-+ if (this.queue.getAndSet(queue) != null) {
-+ throw new IllegalStateException("Already queued!");
-+ }
++ void setQueue(final PrioritizedTaskQueue queue) {
++ this.queue.set(queue);
+ }
+
+ /* priority */
@@ -1901,7 +1902,7 @@ index 0000000000..1dfa8abfd8
+}
diff --git a/src/main/java/com/destroystokyo/paper/io/chunk/ChunkTaskManager.java b/src/main/java/com/destroystokyo/paper/io/chunk/ChunkTaskManager.java
new file mode 100644
-index 0000000000..715a2dd8d2
+index 0000000000..e8282e9781
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/io/chunk/ChunkTaskManager.java
@@ -0,0 +0,0 @@
@@ -1941,7 +1942,9 @@ index 0000000000..715a2dd8d2
+ private final PrioritizedTaskQueue<ChunkTask> chunkTasks = new PrioritizedTaskQueue<>(); // used if async chunks are disabled in config
+
+ protected static QueueExecutorThread<ChunkTask>[] globalWorkers;
++ protected static QueueExecutorThread<ChunkTask> globalUrgentWorker;
+ protected static PrioritizedTaskQueue<ChunkTask> globalQueue;
++ protected static PrioritizedTaskQueue<ChunkTask> globalUrgentQueue;
+
+ protected static final ConcurrentLinkedQueue<Runnable> CHUNK_WAIT_QUEUE = new ConcurrentLinkedQueue<>();
+
@@ -2023,6 +2026,7 @@ index 0000000000..715a2dd8d2
+
+ globalWorkers = new QueueExecutorThread[threads];
+ globalQueue = new PrioritizedTaskQueue<>();
++ globalUrgentQueue = new PrioritizedTaskQueue<>();
+
+ for (int i = 0; i < threads; ++i) {
+ globalWorkers[i] = new QueueExecutorThread<>(globalQueue, (long)0.10e6); //0.1ms
@@ -2034,6 +2038,15 @@ index 0000000000..715a2dd8d2
+
+ globalWorkers[i].start();
+ }
++
++ globalUrgentWorker = new QueueExecutorThread<>(globalUrgentQueue, (long)0.10e6); //0.1ms
++ globalUrgentWorker.setName("Paper Async Chunk Urgent Task Thread");
++ globalUrgentWorker.setPriority(Thread.NORM_PRIORITY+1);
++ globalUrgentWorker.setUncaughtExceptionHandler((final Thread thread, final Throwable throwable) -> {
++ PaperFileIOThread.LOGGER.fatal("Thread '" + thread.getName() + "' threw an uncaught exception!", throwable);
++ });
++
++ globalUrgentWorker.start();
+ }
+
+ /**
@@ -2284,6 +2297,7 @@ index 0000000000..715a2dd8d2
+ worker.flush();
+ }
+ }
++ globalUrgentWorker.flush();
+
+ // flush again since tasks we execute async saves
+ drainChunkWaitQueue();
@@ -2316,20 +2330,30 @@ index 0000000000..715a2dd8d2
+ public void raisePriority(final int chunkX, final int chunkZ, final int priority) {
+ final Long chunkKey = Long.valueOf(IOUtil.getCoordinateKey(chunkX, chunkZ));
+
-+ ChunkSaveTask chunkSaveTask = this.chunkSaveTasks.get(chunkKey);
++ ChunkTask chunkSaveTask = this.chunkSaveTasks.get(chunkKey);
+ if (chunkSaveTask != null) {
-+ final boolean raised = chunkSaveTask.raisePriority(priority);
-+ if (chunkSaveTask.isScheduled() && raised) {
-+ // only notify if we're in queue to be executed
-+ this.internalScheduleNotify();
-+ }
++ // don't bump save into urgent queue
++ raiseTaskPriority(chunkSaveTask, priority != PrioritizedTaskQueue.HIGHEST_PRIORITY ? priority : PrioritizedTaskQueue.HIGH_PRIORITY);
+ }
+
+ ChunkLoadTask chunkLoadTask = this.chunkLoadTasks.get(chunkKey);
+ if (chunkLoadTask != null) {
-+ final boolean raised = chunkLoadTask.raisePriority(priority);
-+ if (chunkLoadTask.isScheduled() && raised) {
-+ // only notify if we're in queue to be executed
++ raiseTaskPriority(chunkLoadTask, priority);
++ }
++ }
++
++ private void raiseTaskPriority(ChunkTask task, int priority) {
++ final boolean raised = task.raisePriority(priority);
++ if (task.isScheduled() && raised) {
++ // only notify if we're in queue to be executed
++ if (priority == PrioritizedTaskQueue.HIGHEST_PRIORITY) {
++ // was in another queue but became urgent later, add to urgent queue and the previous
++ // queue will just have to ignore this task if it has already been started.
++ // Ultimately, we now have 2 potential queues that can pull it out whoever gets it first
++ // but the urgent queue has dedicated thread(s) so it's likely to win....
++ globalUrgentQueue.add(task);
++ this.internalScheduleNotifyUrgent();
++ } else {
+ this.internalScheduleNotify();
+ }
+ }
@@ -2343,8 +2367,14 @@ index 0000000000..715a2dd8d2
+
+ // It's important we order the task to be executed before notifying. Avoid a race condition where the worker thread
+ // wakes up and goes to sleep before we actually schedule (or it's just about to sleep)
-+ this.queue.add(task);
-+ this.internalScheduleNotify();
++ if (task.getPriority() == PrioritizedTaskQueue.HIGHEST_PRIORITY) {
++ globalUrgentQueue.add(task);
++ this.internalScheduleNotifyUrgent();
++ } else {
++ this.queue.add(task);
++ this.internalScheduleNotify();
++ }
++
+ }
+
+ protected void internalScheduleNotify() {
@@ -2359,6 +2389,14 @@ index 0000000000..715a2dd8d2
+ }
+ }
+
++
++ protected void internalScheduleNotifyUrgent() {
++ if (globalUrgentWorker == null) {
++ return;
++ }
++ globalUrgentWorker.notifyTasks();
++ }
++
+}
diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
index b582171c51..03d7ce8294 100644
@@ -2800,7 +2838,7 @@ index a950ad801d..26f1a4b095 100644
nbttagcompound1.set("PostProcessing", a(ichunkaccess.l()));
diff --git a/src/main/java/net/minecraft/server/ChunkStatus.java b/src/main/java/net/minecraft/server/ChunkStatus.java
-index 134a4f0b7d..88f1674616 100644
+index 134a4f0b7d..40ce30cdc2 100644
--- a/src/main/java/net/minecraft/server/ChunkStatus.java
+++ b/src/main/java/net/minecraft/server/ChunkStatus.java
@@ -0,0 +0,0 @@ public class ChunkStatus {
@@ -2811,6 +2849,30 @@ index 134a4f0b7d..88f1674616 100644
public static int a(ChunkStatus chunkstatus) {
return ChunkStatus.r.getInt(chunkstatus.c());
}
+@@ -0,0 +0,0 @@ public class ChunkStatus {
+ this.t = chunkstatus == null ? 0 : chunkstatus.c() + 1;
+ }
+
++ public int getStatusIndex() { return c(); } // Paper - OBFHELPER
+ public int c() {
+ return this.t;
+ }
+@@ -0,0 +0,0 @@ public class ChunkStatus {
+ return this.w.doWork(this, worldserver, definedstructuremanager, lightenginethreaded, function, ichunkaccess);
+ }
+
++ public int getNeighborRadius() { return this.f(); } // Paper - OBFHELPER
+ public int f() {
+ return this.x;
+ }
+@@ -0,0 +0,0 @@ public class ChunkStatus {
+ return this.z;
+ }
+
++ public boolean isAtLeastStatus(ChunkStatus chunkstatus) { return b(chunkstatus); } // Paper - OBFHELPER
+ public boolean b(ChunkStatus chunkstatus) {
+ return this.c() >= chunkstatus.c();
+ }
diff --git a/src/main/java/net/minecraft/server/IAsyncTaskHandler.java b/src/main/java/net/minecraft/server/IAsyncTaskHandler.java
index 7e5ece9d50..cfe43e882e 100644
--- a/src/main/java/net/minecraft/server/IAsyncTaskHandler.java
@@ -3055,7 +3117,7 @@ index 50135446f7..b38bc67758 100644
completablefuture = (CompletableFuture) this.statusFutures.get(i);
if (completablefuture != null) {
diff --git a/src/main/java/net/minecraft/server/PlayerChunkMap.java b/src/main/java/net/minecraft/server/PlayerChunkMap.java
-index 7dec34cb76..893c542f57 100644
+index b4c9d544fe..7e5fa016c7 100644
--- a/src/main/java/net/minecraft/server/PlayerChunkMap.java
+++ b/src/main/java/net/minecraft/server/PlayerChunkMap.java
@@ -0,0 +0,0 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
diff --git a/Spigot-Server-Patches/Expose-MinecraftServer-isRunning.patch b/Spigot-Server-Patches/Expose-MinecraftServer-isRunning.patch
index d7f2ebb361..ce14871511 100644
--- a/Spigot-Server-Patches/Expose-MinecraftServer-isRunning.patch
+++ b/Spigot-Server-Patches/Expose-MinecraftServer-isRunning.patch
@@ -6,7 +6,7 @@ Subject: [PATCH] Expose MinecraftServer#isRunning
This allows for plugins to detect if the server is actually turning off in onDisable rather than just plugins reloading.
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
-index b9a398bc5..32121e87b 100644
+index 53b71b7915..1a3c6aae18 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -0,0 +0,0 @@ public final class CraftServer implements Server {