How to see the sum of all context switches of all threads within a Java process?

I am running pidstat on CentOS linux to monitor a Java application. When I feed the java pid to pidstat it never shows any context switches.

top
2407 root      20   0 7939m 4.2g  11m S 129.3 58.4 138:47.08 java

pidstat -w -I -p 2407 3

09:53:41 AM       PID   cswch/s nvcswch/s  Command
09:53:44 AM      2407      0.00      0.00  java

I have to find the pid of a specific Java thread (using top -H) to see the context switches.

top -H
2915 root      20   0 7939m 4.2g  11m R 22.8 58.3  17:36.93 java

pidstat -w -I -p 2915 3

09:53:41 AM       PID   cswch/s nvcswch/s  Command
10:10:11 AM      2915    643.67    230.33  java

How can you see the sum of all context switches of all threads within a Java process?

Answer

If you are looking to do this in Java, then the API doesn’t provide such means. You will have to resort to a platform dependent way of doing this.

You could perhaps use JNI/JNA to do this natively for different operating systems:

• Windows – Performance Counters
• Linux – getrusage

---

If you mean to do this with pidstat, then you should really ask this question in SuperUser.com. However, as far as I know you can add -t to your pidstat command, so that it looks like so:

pidstat -w -I -t -p <pid> 3

It will list stats for all the threads of the process.