Remi,
Keep in mind this is still suboptimal.
if you run 2 tasks per node, there is a risks threads from different
ranks end up bound to the same core, which means time sharing and a drop
in performance.
Cheers,
Gilles
On 6/22/2016 4:45 PM, remi marchal wrote:
Dear Gilles,
Thanks a lot.
The mpirun --bind-to-none solve the problem.
Thanks a lot,
Regards,
Rémi
Le 22 juin 2016 à 09:34, Gilles Gouaillardet <gil...@rist.or.jp
<mailto:gil...@rist.or.jp>> a écrit :
Remi,
in the same environment, can you
mpirun -np 1 grep Cpus_allowed_list /proc/self/status
it is likely Open MPI allows only one core, and in this case, i
suspect MKL refuses to do some time sharing and hence transparently
reduce the number of threads to 1.
/* unless it *does* time sharing, and you observed 4 threads with the
performance of one */
mpirun --bind-to none ...
will tell Open MPI *not* to bind on one core, and that should help a bit.
note this is suboptimal, you should really ask mpirun to allocate 4
cores per task, but i cannot remember the correct command line for that
Cheers,
Gilles
On 6/22/2016 4:17 PM, remi marchal wrote:
Dear openmpi users,
Today, I faced a strange problem.
I am compiling a quantum chemistry software (CASTEP-16) using
intel16, mkl threaded libraries and openmpi-18.1.
The compilation works fine.
When I ask for MKL_NUM_THREAD=4 and call the program in serial mode
(without mpirun), it works perfectly and use 4 threads.
However, when I start the program with mpirun, even with 1 mpi
process, the program ran but only with 1 thread.
I never add such kind of trouble.
Does anyone have an explanation.
Regards,
Rémi
_______________________________________________
users mailing list
us...@open-mpi.org
Subscription:https://www.open-mpi.org/mailman/listinfo.cgi/users
Link to this
post:http://www.open-mpi.org/community/lists/users/2016/06/29495.php
_______________________________________________
users mailing list
us...@open-mpi.org <mailto:us...@open-mpi.org>
Subscription: https://www.open-mpi.org/mailman/listinfo.cgi/users
Link to this post:
http://www.open-mpi.org/community/lists/users/2016/06/29497.php
_______________________________________________
users mailing list
us...@open-mpi.org
Subscription: https://www.open-mpi.org/mailman/listinfo.cgi/users
Link to this post:
http://www.open-mpi.org/community/lists/users/2016/06/29498.php
