Re: work-load imbalance

From: Pedro Colin <p.colin_at_astrosmo.unam.mx>
Date: Thu, 2 Nov 2006 10:35:44 -0600 (CST)

Hi Luca,

> I mean, although your procs are dual core, you have actually 4 processing
> units (and that's the factor ~2 that you get).

I am not an expert on these computer things but I thought dual core
essentially meant 2 procs. In fact, a factor of 2 with lower speed procs
(2.0 versus 2.4 Ghz) means that the performance of my quad is more than
simply 4 procs.

> do the cpus have dual channel memory access?
> just a hint..


16 GB DDR1-400 ECC REG LP(64x8)(1GB x 16)

That is 16 GB de RAM.

Thanks for replying.

Pedro

>
> 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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-- 
Dr. Pedro Colin
Investigador Titular A
CRyA, UNAM, Morelia, Mich.
Received on 2006-11-02 17:36:04

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