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From "Steve G.B." <>
Subject RE: Installing Multiple Instances on Windows Server 2003
Date Wed, 03 Sep 2008 07:44:05 GMT

Found the issue.

I just needed a for cicle with millions of loops.

There was only kernel calls that saturated CPU till 45-50%.
A resource was waiting something. Don't know if it was the HDD or the

I have to check.
Thanks for the tip, Peter :)

Peter Crowther wrote:
>> From: Steve G.B. []
>> I've created a VM with 4 VCores, and all of the cores are
>> allocated to the VM.
> OK, so 50% CPU = 2 cores maxed out.  Out of interest, is it 25% with only
> one Tomcat started?
>> I'm using Sun JVM 1.6, and stressing the Guest with
>> Loadrunner on another
>> machine (if you ask: this machine with loadrunner isn't the
>> bottleneck)
>> No Databases, no I/O requests, no Network saturation.
> OK.
> Given that you're getting exactly 50% CPU use (it *is* exact, right?) that
> indicates the test harness is very unlikely to be the problem.  It would
> almost certainly bottleneck at some other CPU value.
>> that's why I think it's the JVM.
>> For my tests I used the standard demo webapp in Loarunner
>> (Mercury Tours),
>> and a couple of stupid jsp pages. So Apache and Tomcat both.
> I'll highlight that to the folks who know the demo app better: does it run
> properly under load?  I'd assume so...
>> Fun thing is that when using Tomcat and Apache combined, I
>> can get an 80-85% CPU Utilization.
> Yes.  If you've got httpd passing everything through it as well, you'll
> increase the CPU load - that's expected!
>> Problem is that for my tests I need
>> something more simple and the same server.
> Yes.  Why add complexity when it's not required? :-)
>> How do you saturate an 8-core host?
> With some reasonably complex code in the JSPs :-).  Out of interest, if
> your JSPs call something that loops a couple of million times before
> returning, what happens to the CPU use?
>                 - Peter
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