Re: Java application cpu utilization spiking ... taking a long time tocancel.

Hi David,

Probably garbage collection, although that won't always show a spike. I went through a similar issue with WAS over the last few months. The asynch collector can really run into problems if it can't complete (usually do to disk swap) before another memory allocation request comes through. It's very similar to thrashing.

The ENDJOB doesn't appear to take effect because it wants to clean up the memory before responding.


Joe Sam

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----- Original Message ----- From: "David Gibbs" <david@xxxxxxxxxxxx>
To: "Java Programming on and around the iSeries / AS400" <java400-l@xxxxxxxxxxxx>
Cc: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
Sent: Monday, May 18, 2009 10:03 AM
Subject: Java application cpu utilization spiking ... taking a long time tocancel.

Folks:

I'm cross posting this to both JAVA400-L and MIDRANGE-L, as I think it might not be specific to Java.

I've got a java application that's running on a customers system that is periodically spiking in it's cpu utilization.

The really odd thing about this is that an ENDJOB OPTION(*IMMED) takes a long time to kill the job ... sometimes hours.

I had them do a DMPJVM on the application and all the threads were either sleeping, waiting, timed wait, or java wait. I can't figure out where the cpu utilization is happening.

Any ideas?

Thanks!

david

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