Paper/patches/server/0226-Add-Early-Warning-Feature-to-WatchDog.patch
Bjarne Koll c5a10665b8
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.
2024-09-19 16:36:07 +02:00

160 lines
10 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: miclebrick <miclebrick@outlook.com>
Date: Wed, 8 Aug 2018 15:30:52 -0400
Subject: [PATCH] Add Early Warning Feature to WatchDog
Detect when the server has been hung for a long duration, and start printing
thread dumps at an interval until the point of crash.
This will help diagnose what was going on in that time before the crash.
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index cc0968182ab597892dbae8dd9b3e803fb62b7065..2d5ae71c143556a938f078d2fb84cab7bd4f789b 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -1107,6 +1107,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
this.status = this.buildServerStatus();
// Spigot start
+ org.spigotmc.WatchdogThread.hasStarted = true; // Paper
Arrays.fill( this.recentTps, 20 );
// Paper start - further improve server tick loop
long tickSection = Util.getNanos();
diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
index c466ec011d059b9960606ef2ee51ea3a3a65f8d0..baf93b5d5883d0a5c360f1a475949804b7907636 100644
--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
@@ -216,6 +216,7 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
this.paperConfigurations.initializeGlobalConfiguration(this.registryAccess());
this.paperConfigurations.initializeWorldDefaultsConfiguration(this.registryAccess());
// Paper end - initialize global and world-defaults configuration
+ org.spigotmc.WatchdogThread.doStart(org.spigotmc.SpigotConfig.timeoutTime, org.spigotmc.SpigotConfig.restartOnCrash); // Paper - start watchdog thread
io.papermc.paper.command.PaperCommands.registerCommands(this); // Paper - setup /paper command
com.destroystokyo.paper.Metrics.PaperMetrics.startMetrics(); // Paper - start metrics
com.destroystokyo.paper.VersionHistoryManager.INSTANCE.getClass(); // Paper - load version history now
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index 5478c159843a74ea90b2b1c4d5eb3c92a910a857..ffe53ca530da2b2a1b28c7ee59a7f5599949a0a1 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -962,6 +962,7 @@ public final class CraftServer implements Server {
@Override
public void reload() {
+ org.spigotmc.WatchdogThread.hasStarted = false; // Paper - Disable watchdog early timeout on reload
this.reloadCount++;
this.configuration = YamlConfiguration.loadConfiguration(this.getConfigFile());
this.commandsConfiguration = YamlConfiguration.loadConfiguration(this.getCommandsConfigFile());
@@ -1053,6 +1054,7 @@ public final class CraftServer implements Server {
this.enablePlugins(PluginLoadOrder.POSTWORLD);
if (io.papermc.paper.plugin.PluginInitializerManager.instance().pluginRemapper != null) io.papermc.paper.plugin.PluginInitializerManager.instance().pluginRemapper.pluginsEnabled(); // Paper - Remap plugins
this.getPluginManager().callEvent(new ServerLoadEvent(ServerLoadEvent.LoadType.RELOAD));
+ org.spigotmc.WatchdogThread.hasStarted = true; // Paper - Disable watchdog early timeout on reload
}
@Override
diff --git a/src/main/java/org/spigotmc/SpigotConfig.java b/src/main/java/org/spigotmc/SpigotConfig.java
index b97ff4a9b69699577bf8cde0869b70353101ef46..85f3433860abd91a89961907940a807a8b190a46 100644
--- a/src/main/java/org/spigotmc/SpigotConfig.java
+++ b/src/main/java/org/spigotmc/SpigotConfig.java
@@ -225,7 +225,7 @@ public class SpigotConfig
SpigotConfig.restartScript = SpigotConfig.getString( "settings.restart-script", SpigotConfig.restartScript );
SpigotConfig.restartMessage = SpigotConfig.transform( SpigotConfig.getString( "messages.restart", "Server is restarting" ) );
SpigotConfig.commands.put( "restart", new RestartCommand( "restart" ) );
- WatchdogThread.doStart( SpigotConfig.timeoutTime, SpigotConfig.restartOnCrash );
+ // WatchdogThread.doStart( SpigotConfig.timeoutTime, SpigotConfig.restartOnCrash ); // Paper - moved to after paper config initialization
}
public static boolean bungee;
diff --git a/src/main/java/org/spigotmc/WatchdogThread.java b/src/main/java/org/spigotmc/WatchdogThread.java
index 81ccbe2533e6fc5899d6c068e421e0d7f1351d34..ad282d34919716b75acd10426cd071da9d064a51 100644
--- a/src/main/java/org/spigotmc/WatchdogThread.java
+++ b/src/main/java/org/spigotmc/WatchdogThread.java
@@ -14,6 +14,10 @@ public class WatchdogThread extends Thread
private static WatchdogThread instance;
private long timeoutTime;
private boolean restart;
+ private final long earlyWarningEvery; // Paper - Timeout time for just printing a dump but not restarting
+ private final long earlyWarningDelay; // Paper
+ public static volatile boolean hasStarted; // Paper
+ private long lastEarlyWarning; // Paper - Keep track of short dump times to avoid spamming console with short dumps
private volatile long lastTick;
private volatile boolean stopping;
@@ -22,6 +26,8 @@ public class WatchdogThread extends Thread
super( "Paper Watchdog Thread" );
this.timeoutTime = timeoutTime;
this.restart = restart;
+ earlyWarningEvery = Math.min(io.papermc.paper.configuration.GlobalConfiguration.get().watchdog.earlyWarningEvery, timeoutTime); // Paper
+ earlyWarningDelay = Math.min(io.papermc.paper.configuration.GlobalConfiguration.get().watchdog.earlyWarningDelay, timeoutTime); // Paper
}
private static long monotonicMillis()
@@ -61,9 +67,18 @@ public class WatchdogThread extends Thread
while ( !this.stopping )
{
//
- if ( this.lastTick != 0 && this.timeoutTime > 0 && WatchdogThread.monotonicMillis() > this.lastTick + this.timeoutTime && !Boolean.getBoolean("disable.watchdog")) // Paper - Add property to disable
+ // Paper start
+ Logger log = Bukkit.getServer().getLogger();
+ long currentTime = WatchdogThread.monotonicMillis();
+ if ( this.lastTick != 0 && this.timeoutTime > 0 && currentTime > this.lastTick + this.earlyWarningEvery && !Boolean.getBoolean("disable.watchdog")) // Paper - Add property to disable
{
- Logger log = Bukkit.getServer().getLogger();
+ boolean isLongTimeout = currentTime > lastTick + timeoutTime;
+ // Don't spam early warning dumps
+ if ( !isLongTimeout && (earlyWarningEvery <= 0 || !hasStarted || currentTime < lastEarlyWarning + earlyWarningEvery || currentTime < lastTick + earlyWarningDelay)) continue;
+ if ( !isLongTimeout && MinecraftServer.getServer().hasStopped()) continue; // Don't spam early watchdog warnings during shutdown, we'll come back to this...
+ lastEarlyWarning = currentTime;
+ if (isLongTimeout) {
+ // Paper end
log.log( Level.SEVERE, "------------------------------" );
log.log( Level.SEVERE, "The server has stopped responding! This is (probably) not a Paper bug." ); // Paper
log.log( Level.SEVERE, "If you see a plugin in the Server thread dump below, then please report it to that author" );
@@ -92,29 +107,45 @@ public class WatchdogThread extends Thread
}
}
// Paper end
+ } else
+ {
+ log.log(Level.SEVERE, "--- DO NOT REPORT THIS TO PAPER - THIS IS NOT A BUG OR A CRASH - " + Bukkit.getServer().getVersion() + " ---");
+ log.log(Level.SEVERE, "The server has not responded for " + (currentTime - lastTick) / 1000 + " seconds! Creating thread dump");
+ }
+ // Paper end - Different message for short timeout
log.log( Level.SEVERE, "------------------------------" );
log.log( Level.SEVERE, "Server thread dump (Look for plugins here before reporting to Paper!):" ); // Paper
WatchdogThread.dumpThread( ManagementFactory.getThreadMXBean().getThreadInfo( MinecraftServer.getServer().serverThread.getId(), Integer.MAX_VALUE ), log );
log.log( Level.SEVERE, "------------------------------" );
//
+ // Paper start - Only print full dump on long timeouts
+ if ( isLongTimeout )
+ {
log.log( Level.SEVERE, "Entire Thread Dump:" );
ThreadInfo[] threads = ManagementFactory.getThreadMXBean().dumpAllThreads( true, true );
for ( ThreadInfo thread : threads )
{
WatchdogThread.dumpThread( thread, log );
}
+ } else {
+ log.log(Level.SEVERE, "--- DO NOT REPORT THIS TO PAPER - THIS IS NOT A BUG OR A CRASH ---");
+ }
+
log.log( Level.SEVERE, "------------------------------" );
+ if ( isLongTimeout )
+ {
if ( this.restart && !MinecraftServer.getServer().hasStopped() )
{
RestartCommand.restart();
}
break;
+ } // Paper end
}
try
{
- sleep( 10000 );
+ sleep( 1000 ); // Paper - Reduce check time to every second instead of every ten seconds, more consistent and allows for short timeout
} catch ( InterruptedException ex )
{
this.interrupt();