If you want to take thread dumps to identify which Java threads consume high cpu, please see How do I identify high CPU utilization by Java threads on Linux/Solaris and use the attached sample script in the article.It is reported that a slowness in response time can be observed when running jstack in some scenarios. In some circumstances running jstack might cause a performance impact.F, -m, etc.) and/or thread dump tools are not able to parse the output, so if any other options besides -l are proposed, be sure to test capturing and parsing the output. There are known bugs related to using other jstack options (e.g.Please see Getting "Unable to open socket file" message when executing jstack / jmap / jcmd and unable to generate a thread dump / heap dump for more details. You need to make sure to execute jstack command from the same user as the java process.Threads in the (T) state will receive the signal for a thread dump however, output will be delayed until the process continues. nohup $JBOSS_HOME/bin/run.sh -c yourinstancename $JBOSS_OPTS > console-$(date +%Y%m%d).out 2>&1 puts the target Java process in a "trace stop" (T) state. Otherwise, redirect stdout to a file on startup. If the Java application is started with a service script that logs console output, the thread dumps will be in the console log. Use the below command to start JBoss instance and then use kill -3 to generate the thread dumps. threaddump_solaris-continuous.sh JAVA_PIDīe sure to test the script before the issue happens to make sure it runs properly in your environment. It will capture thread dumps spaced 20 seconds apart (modify as needed), passing in the Java process ID as an argument.
Make the script executable with chmod 755. Option 3: kill -3 Linux script (continuous)ĭownload either threaddump_linux-continuous.sh.tar.gz or threaddump_solaris-continuous.sh.tar.gz, and extract the script. threaddump_solaris.sh JAVA_PIDīe sure to test the script before the issue happens to make sure it runs properly in your environment.
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The script will capture a series of 6 thread dumps spaced 20 seconds apart (this can be modified as needed), passing in the Java process ID as an argument. Option 2: kill -3 Linux script (not-continuous)ĭownload either threaddump_linux.sh.tar.gz or threaddump_solaris.sh.tar.gz, and extract the script. using top, a grep on ps -axw, etc.) and send a QUIT signal to the process with the kill -QUIT or kill -3 command 1. Note the process ID number of the Java process (e.g. Execute the following, passing in the Java process ID: jstack -l JAVA_PID > jstack.out it is not desirable to restart the JVM just to redirect standard out). This is useful when redirecting standard out to a file is problematic for some reason (e.g. If using OpenJDK or Sun JDK 1.6 or later, using jstack is an option. Running kill -3 sends a SIGQUIT signal to the JVM, so using this option will cause kill -3 to be ignored. Use jps -lv to find the Java process ID for issuing kill -QUIT or kill -3.īe sure the -Xrs JVM option is not being used, as it causes SIGQUIT and SIGWAITING signals to be ignored. Excessive gc can cause threading issues, so gc and thread dump analysis go hand in hand. Note: Typically gc logging is provided whenever thread dumps are captured.
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