The ABINIT Users Mailing List ( CLOSED )

["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi,

Usually this is true (not only for Abinit)  and not well reproduce by
HPC benchmarks because intel has a very big compiler development team
that optimise intel compilers for benchmarks whereas AMD has not.
Therefor if you take a none standard for benchmaring  program/case
(you can even observe that by changing the data in SPEC bechmarks) the
chance are that intel libraries are not specifically tuned for your
non standard case and that AMD processor performed there equally well
as on the benchmark. Consequently has long as you don't work with very
wide spread program available in binary form you are quite likely to
find that AMD proc. are faster than intels.

This was very much true for the P4_xeon to opteron comparison. I'm
almost certain it holds also for the core2 to opteron eventhough much
less critically in favor of opteron.


regards

PMA

On 8/28/07, Xiulin Ruan <ruan@purdue.edu> wrote:
> Thanks for the information. We tested quad-cores and we do find the
> performance is no better than dual-cores. So we will go with dual-core
> processors. One more question. It seems AMD processors have better
> performance than Intel for abinit, right?
>
> Thanks,
>
> Xiulin
>
>
> > -----Original Message-----
> > From: Nicola Marzari [mailto:marzari@mit.edu]
> > Sent: Saturday, August 18, 2007 2:50 PM
> > To: forum@abinit.org
> > Subject: Re: [abinit-forum] computer cluster for parallel computing
> >
> >
> >
> > Also, make sure you really need quad-cores. I've tested other plane-wave
> > electronic structure codes, and never found a case when the quad cores
> > were justified, for the marginal increase of performance compared to two
> > cores - you usually saturate the memory bus very quickly, even with one
> > core.
> >
> > This is even more relevant when you factor in the true costs of air
> > conditioning and electricity.
> >
> >                               nicola
> >
> >
> > Xiulin Ruan wrote:
> > > Thanks a lot for the information. Also, what is the proper amount of
> > memory
> > > per core? Is 4GB good enough?
> > >
> > > Thanks,
> > >
> > > Xiulin
> > >
> > >> -----Original Message-----
> > >> From: Anglade Pierre-Matthieu [mailto:anglade@gmail.com]
> > >> Sent: Friday, August 17, 2007 3:41 PM
> > >> To: forum@abinit.org
> > >> Subject: Re: [abinit-forum] computer cluster for parallel computing
> > >>
> > >> Hi,
> > >>
> > >> Two partial answers for your question:
> > >> - I have never done any benchmarking but infiniband works very well
> > >> for Abinit on "lemaitre" the super computer of the CISM
> > >> - You will find a detailed performance analysis by Torsten Hoefler
> > >> with two different kinds of interconnection here :
> > >> www.unixer.de/publications/img/hoefler-sfb05.pdf
> > >> This might be usefull for your decision.
> > >>
> > >> Regards
> > >>
> > >> PMA
> > >>
> > >> On 8/17/07, Xiulin Ruan <ruan@purdue.edu> wrote:
> > >>> Dear all,
> > >>>
> > >>> We are building a computer cluster to run abinit in the parallel mode.
> > >> We
> > >>> are gonna have two or four nodes, and each node will be
> dual-processor,
> > >>> quad-core. We wonder if the high speed InfiniBand connection is worthy
> > >> to
> > >>> have. Our current jobs include calculating band structure and optical
> > >>> properties of carbon nanotubes and TiO2. Any suggestions?
> > >>>
> > >>> Many thanks,
> > >>>
> > >>> Xiulin
> >
> >
> > --
> > ---------------------------------------------------------------------
> > Prof Nicola Marzari   Department of Materials Science and Engineering
> > 13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
> > tel 617.4522758 fax 2586534 marzari@mit.edu http://quasiamore.mit.edu
>
>


-- 
Pierre-Matthieu Anglade