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Print thread dump on specific signals #27

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merged 3 commits into from
Oct 21, 2024
Merged

Print thread dump on specific signals #27

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67f8796
Add signal handler that prints thread dump
Bouncheck Oct 21, 2024
59432cb
Update tools/stress/src/org/apache/cassandra/stress/Stress.java
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211f2d4
Stress.java
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36 changes: 36 additions & 0 deletions tools/stress/src/org/apache/cassandra/stress/Stress.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,9 @@
package org.apache.cassandra.stress;

import java.io.*;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;
import java.net.Socket;
import java.net.SocketException;

Expand All @@ -27,6 +30,9 @@
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.WindowsTimer;

import sun.misc.Signal;
import sun.misc.SignalHandler;
Comment on lines +33 to +34
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Are the sun.misc.* inside the internal parts of JDK and shouldn't be accessed?

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Yes, but outside of shutdown hooks I don't know of a way to do this. If it ever gets removed I assume there will be something else for signal handling and in that case this change should be easy to port or ditch altogether since it does not go too deep.

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You are right, there is no other way to get to the Unix signals, and handle specific signal through Java Public APIs


public final class Stress
{

Expand Down Expand Up @@ -56,6 +62,8 @@ public final class Stress

public static void main(String[] arguments) throws Exception
{
registerSignalHandler();

if (FBUtilities.isWindows)
WindowsTimer.startTimerPeriod(1);

Expand Down Expand Up @@ -196,4 +204,32 @@ public void run()
}
}

private static String threadDump(boolean lockedMonitors, boolean lockedSynchronizers) {
StringBuffer threadDump = new StringBuffer(System.lineSeparator());
ThreadMXBean threadMXBean = ManagementFactory.getThreadMXBean();
for(ThreadInfo threadInfo : threadMXBean.dumpAllThreads(lockedMonitors, lockedSynchronizers)) {
threadDump.append(threadInfo.toString());
}
return threadDump.toString();
}

private static void registerSignalHandler() {
SignalHandler handler = signal -> {
System.out.println("Caught signal: " + signal.getName());
System.out.println(threadDump(true, true));
switch (signal.getName()) {
case "ABRT":
System.exit(128 + 6);
case "TERM":
System.exit(128 + 15);
case "INT":
System.exit(128 + 2);
default:
System.exit(1);
}
};
Signal.handle(new Signal("ABRT"), handler);
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Signal.handle(new Signal("TERM"), handler);
Signal.handle(new Signal("INT"), handler);
}
}