Re: sched_domains and Stream benchmark

From: Darren Hart
Date: Mon Apr 26 2004 - 17:32:26 EST


On Tue, 2004-04-20 at 11:58, Andi Kleen wrote:
> Darren Hart <dvhltc@xxxxxxxxxx> writes:
>
> > Andi,
> >
> > You have mentioned the stream benchmark when reporting on the
> > performance of the Opteron NUMA sched-domains scheduler. I am trying to
> > reproduce your results and am struggling with the benchmark. Can you
> > rpovide the details of the tests you ran. Namely your compiler
> > settings, compile command line, and your value of N. Also I didn't see
> > how to specify the number of threads to run, how did you specify that?
> > I have a 4 way 1.4 GHz 1MB cache opteron machine with 7 GB of RAM.
>
> I didn't actually compile them myself; someone sent me executables
> compiled with the PGI compiler. Maybe your compiler has a different
> runtime and behaves differently?
>
> You can find them and my test script that tests everything in
> ftp://ftp.suse.com/pub/people/ak/bench/stream.tar.gz

Thanks Andi,

I noticed your binary ran with N=2000000 which is only sufficient for a
2 proc 1 MB cache opteron box according to the documentation on the
stream faq. I also noticed wide variation in results (25% or so) when
running with 4 threads on a 4 proc opteron on linux-2.6.5-mm5. Can you
provide me with the specs of the system you ran your tests on?

Thanks,

Darren

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