Strange Problem in Multiple JVM threads using Sockets

[Meenakshi Sundaram]

Hi,
Am running a Java application on a 4 CPU HP-UX machine (L2000). This application uses more than 40 threads that do Socket I/O Operations at any instant.
Am facing a strange problem now. At times my CPU usage goes high (near 375%) and it is the above threads that account for such a high utilisation. It happens only at times. I feel that the socket operations happen in bursts during that period.
When the system is normal the CPU utilisation is only 130% and hardly 10 of the above threads run simulataneously. But during the above (problem) period nearly all the threads are running.
Have any one of you faced this? Also can you please suggest me a way out of this !!

Regards,
M Meenakshi Sundaram

[Helen French]

Hi Meenakshi,

Try updating your system with the latest patches. That normally resolve all performance issues.

HTH,
Shiju

[Meenakshi Sundaram]

Hi,
I had actually installed all the patches (when I had posted the message). But of no help. Then we switched to JDK1.3.1. This problem doesn't exist any more.

Thanks for your help !!

Regards,
M Meenakshi Sundaram

[Chris De Angelis]

Hi Meenakshi,

I don't know why you're seeing the sudden spike in CPU utilization, but you might need to adjust your kernel parameters if you have a Java process using lots of threads and open files/file descriptors.

See this page for details:

http://www.hp.com/products1/unix/java/infolibrary/prog_guide/java1_3/configuration.html

Good luck.

- Chris