Thanks for the answer... It actually brought me another question: can
different implementations of MPI have high difference on execution times?
>From: Tim Prince <n8tm_at_[hidden]>
>Reply-To: tprince_at_[hidden], General LAM/MPI mailing list
><lam_at_[hidden]>
>To: General LAM/MPI mailing list <lam_at_[hidden]>
>Subject: Re: LAM: Theorical question about parallel computing
>Date: Wed, 11 Jul 2007 20:09:51 -0700
>
>pedropetrovitch_at_[hidden] wrote:
> > Altough my question isnt directly about LAM/MPI it kind of answers me a
>lot
> > of things that I need to know if I need to use MPI or not. Here it goes:
>Is
> > it possible to make a parallel algorithm (using MPI) running in a single
> > machine/node (with many process running on it, i.e., mpirun -np 10 main
>and
> > only one hardware processor) to run faster than a serial one on the same
> > conditions? Thanks a lot for the atention. Any help would be
>appreciated.
>
>Theoretically, possibly with some very strange application designed so
>that a single process doesn't use all the resources, or resources such
>as cache/memory can't be made available to a single process.
>Practically, no, the single node MPI speedup of a normal application is
>limited to the number of separate processors (e.g. cores) on the node,
>and would normally be optimized by running one process per core.
>If there is an advantage for MPI over threading (e.g. OpenMP) it is
>usually related to better cache and memory locality of the MPI processes.
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