Re: work-load imbalance

From: Luca Tornatore <torna_at_sissa.it>
Date: Thu, 2 Nov 2006 10:53:53 +0100

Hi Pedro,
your problem may be related to the memory access.. ?
I mean, although your procs are dual core, you have actually 4 processing
units (and that's the factor ~2 that you get).
do the cpus have dual channel memory access?
just a hint..

cheers,
luca

On Wed November 1 2006 18:46, Pedro Colin wrote:
> Hi,
>
> Does anyone have a sort of recipe to optimize the work load balance and
> thus to improve the multi-cpu computer performance? I just got a quad with
> double core opteron 64bits proccesors at 2.0 Ghz, so 8 procs in total.
> When I compare the wall time of this computer with a dual opteron at 2.4
> Ghz (single core) in a Gadget2 simulation (N-body only) I only get a
> factor of 2 gain. When I look at the timings.txt I see that this is due to
> work-load imbalance. The procs in the quad run on average twice slower
> than those in the dual. I have made some changes to *BufferSize* and
> *PartAllocFactor* and have got some improvement but still I think I am not
> getting the most of it.
>
> Cheers,
>
> Pedro
>
>
>
>
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Received on 2006-11-02 10:54:22

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