Hello,

 

I always wanted to ask this question and I believe this is the right platform ,

ever since I step into websphere world I see my all websphere server consume huge memory but very minimum cpu says 5 to 10% only

 So I wanted to clear is it normal behavior or is there any way I can make websphere eat more CPU so I can get hidden performance which may be I am not getting ?

Hello,
    I find memory capacity is the culprit of performance problem much more often than its computing power as well.
    This may be dued to the fact that the growth of memory consumption is not as fast as the development of CPU speed (double each year according to Moore's law).

    I find the cpu-bound system mostly dued to the large number of records processed which occurs in batch applications. Moreover, many computing intensive applications such as bioinformatic, scientific, cryptography use a different variation of application serving pattern such as grid computing as well.

    Naturally, during the performance tuning session, you will encounter OutOfMemoryError issue first. This is mostly dued to bad programming practice (e.g. large object, unmanaged java collection). When this issue is overcomed and you ramp up the number of concurrent session, you may encounter locking and concurrency issue which can occur either internal to JVM (sychronized) or external to JVM such as database deadlocks.
    If you drive up concurrency high enough, then you are likely to see CPU capacity as your next bottleneck.

    This is my experience. Others' mileage may differ. I just think of it as the legacy of Moore's law. :-)

thanks for replay

we have been there , we had to restart our server every night to sustain heap problem but since we moved to new WAS 6.1 and 8 that problem is almost solve
and not to mention DB lock problem is always there ,
but the reason I am raising this question is on every websphere installation (6 NOS)

I see no CPU consumption but RAM , So I though may be as I can control MEM use by JVM size I can control CPU also!!

let me tell you in two lines 

1) It depends on type of the application you are running on websphere

2) for example : If your application is thread intensive ... you see even CPU usage going up . 

If you are seeing your memory creep up to the point that you need to restart your servers every night it sounds like you have a problem in an application. I posted the items below in a different post but you may want to look into them both to help you analyze the problem and hopefully get it fixed with in the app.

You may want to look at the ISA toll it has a memory analyzer that has help me in the past with a runaway application.

www-01.ibm.com/software/support/isa/

 You can also enable Performance Monitoring Infrastructure (PMI) within WebSphere. But I caution you on doing so in production.

 publib.boulder.ibm.com/infocenter/wasinf...