On Feb 14, 2011, at 9:35 AM, Siew Yin Chan wrote:
> 1. I tried Open MPI 1.5.1 before turning to hwloc-bind. Yep. Open MPI 1.5.1
> does provide the --bycore and --bind-to-core option, but this option seems to
> bind processes to cores on my machine according to the *physical* indexes:
FWIW, you
Brice Goglin, le Mon 14 Feb 2011 07:56:56 +0100, a écrit :
> The operating system decides where each process runs (according to the
> binding). It usually has no knowledge of MPI ranks. And I don't think it looks
> at the PID numbers during the scheduling.
It doesn't either, indeed.
Samuel
Le 14/02/2011 07:43, Siew Yin Chan a écrit :
>
>>
>>
>
> No. Each hwloc-bind command in the mpirun above doesn't know that
> there are other hwloc-bind instances on the same machine. All of
> them bind their process to all cores in the first socket.
>
> => Agree. For socket:0.core:0-3
