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> 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 <mailto:us...@open-mpi.org> >> Subscription: https://www.open-mpi.org/mailman/listinfo.cgi/users >> <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 >> <http://www.open-mpi.org/community/lists/users/2016/06/29495.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/2016/06/29497.php
