Ok, thank you for your answer. I think this rankfile feature is very
interesting to run some jobs like MPMD jobs or hybrid jobs
(multithreaded or GPU for examples).
Regards,
--
--
NGUYEN Laurent
HPC Engineer
CS:SI
email: laurent.ngu...@c-s.fr
web: http://www.c-s.fr
CS:SI
22 avenue Galilée
92350 Le Plessis Robinson
Terry Dontje <terry.don...@oracle.com> a écrit :
NGUYEN Laurent wrote:
Hello,
I'm trying to understand the difference between theses two options:
" --mca mpi_paffinity_alone 1 "
and
" --bind-to-core "
To me, it's the same thing (may be paffinity have maffinity in
addition) but the purpose af theses options is to bind MPI process
to processors. Which is the best to obtain performances?
They are essentially the same thing. The history is that
mpi_paffinity_alone came first. Then a group of us decided that we
wanted to be able to do more than just core binding (like
bind-to-socket and eventually others) so we decided a more
descriptive name made sense. I would suggest sticking with
--bind-to-core just so thinks look clear in your mpirun command.
That and the possibility that one day mpi_paffinity_alone is
deprecated.
I have another question about processes bindings: I use rankfiles
to have a precise binding of my process on processor or socket (it
useful for hybrid computing like pthread or OpenMP). I read you
don't want to maintain this feature: how can I substitute it?
IMO, I say we do support it and will until we find a suitable
replacement (there is a proposal that Jeff and I have bounced around
to each other intermittently but have not brought it to the
community). There have been discussion about lack of testing of
rankfiles and other binding related items making it hard for some to
feel comfortable about putting code back that may have side negative
side affects. But I don't equate that to mean we will not support
or take bug reports on the rankfile feature.
--
Oracle
Terry D. Dontje | Principal Software Engineer
Developer Tools Engineering | +1.650.633.7054
Oracle * - Performance Technologies*
95 Network Drive, Burlington, MA 01803
Email terry.don...@oracle.com <mailto:terry.don...@oracle.com>
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