RE: [Xen-devel] compute performace problem

To:	"David Becker" <becker@xxxxxxxxxxx>, "xen-devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject:	RE: [Xen-devel] compute performace problem
From:	"Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date:	Sat, 23 Apr 2005 22:17:45 +0100
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Thread-topic:	[Xen-devel] compute performace problem

 > One of my users discovered large deviations in execution time 
> for his mpi jobs on xenUs.  I can reproduce the problem 
> running his job on a single VM.  On a native linux box the 
> job completes in 64 secs +/- a second or so.  On a xenU, it 
> completes somewhere between 64 and 250 secs.  This is true on 
> 2.0.5 (2.6.10-xenU) and 2.0-testing(2.6.11-xenU).
> I tried xen-unstable but it seemed any task was taking 4 
> times as long as on 2.0 so I guess its still too unstable.
> 
> Any suggestions I can try?

I'd focus on figuring out why it's always slow on unstable. For 32 bit
non-SMP guests the unstable tree is believed to be at least as stable as
2.0.

Do you get predictable performance running in domain0?

Thanks,
Ian

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RE: [Xen-devel] compute performace problem