Re: Memory Pool Activity Level

On 16/02/2009, at 3:36 PM, Joe Sam Shirah wrote:

The docs use the terms "job" and
"thread" fairly loosely when, in a Java context, they seem to be quite
different to me.

Prior to multi-threaded support being provided by the OS "activity- level" referred to the number of jobs concurrently active in the pool. Once multi-threaded support arrived "activity-level" now refers to the number of concurrent threads active in the pool. Even if performance tuning/work management documentation refers to "jobs" it should be interpreted as meaning "threads".

So, my question: How should we go about determining an appropriate
activity level for the real thing?

A starting point might be to display the WebSphere server job(s) you have running, note the number of concurrent threads in use, add the number of concurrent threads started by your application(s). You will also need to ensure the pool has enough main storage to support the desired activity level. You'll need to know roughly how much main storage each thread will require to set a base storage pool size--or just use a shared pool and let the system work it out. Monitor the pool faulting level to see whether you need to increase storage or decrease the activity-level.

Regards,
Simon Coulter.
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