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From "Vasanth Kumar ravi" <josvasa...@gmail.com>
Subject Re: Question on Performance Tuning
Date Wed, 19 Nov 2008 05:14:47 GMT
Thanks Chuck..
One question thou..

in the JAVA_OPTS do we have to specify -server cos it runs as client by
default.
Will it bring any change to performance ?



On Wed, Nov 19, 2008 at 12:27 PM, Caldarale, Charles R <
Chuck.Caldarale@unisys.com> wrote:

> > From: Vasanth Kumar ravi [mailto:josvasanth@gmail.com]
> > Subject: Question on Performance Tuning
> >
> > We did take thread dumps while performing the test, and
> > found nothing related to application bottlenecks.
>
> Thread dumps are appropriate for diagnosing hangs, but they're not terribly
> useful for analyzing CPU usage.  You'd be better off running a profiler to
> see where time is being spent.  Even the JVM's built-in hprof running in
> sample mode should give you a pretty good idea of where the cycles are going
> (or use JVisualVM).
>
> > Can I get some pointers on anything to be tuned in
> > the tomcat to reduce the cpu utilization.
>
> First, find out what's really using the CPU before fiddling with anything.
>  Tweaking Tomcat is not likely to change much assuming the thread pool and
> heap are adequate for your load.
>
> You've specified several GC options that may or may not be appropriate.
>  Unless you've proven that changing NewRatio, NewSize, MaxNewSize, and
> SurvivorRatio actually helps your throughput, you're likely better off
> leaving them alone.  128M MaxPermSize may be too small if you have a lot of
> classes in your webapps.  Enabling concurrent GC produces more regular
> response times, but will actually *reduce* throughput in most cases.
>
> These might help slightly:
> * Remove AspectJ.
> * Turn off PrintGCDetails.
> * Remove unused webapps.
> * Precompile JSPs.
> * Turn off auto-deployment.
> * Turn off monitored resources.
> * Set the parameters for the JSP servlet (in conf/web.xml) for production.
>
>  - Chuck
>
>
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-- 
Regards&Thanks,
Vasanth Kumar Ravi

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