With an OMPI that old, it’s anyone’s guess - I have no idea.
> On Apr 15, 2015, at 4:12 AM, cristian <cristian.r...@inria.fr> wrote: > > Hello, > > I noticed when performing a profiling of an application that the MPI_init() > function takes a considerable amount of time. > There is a big difference when running 32 processes over 32 machines and 32 > processes over 8 machines (Each machine has 8 cores). > These are the results of the profiling: > > > Results for 32 cores (8 machines) > > Group.1 percent usec > 38 SSOR 79.1125 2557445.625 > 7 EXCHANGE_1 31.8125 33.250 > 24 MPI_Recv() 26.0750 33.375 > 2 BLTS 24.7500 103.125 > 3 BUTS 22.2375 92.500 > 12 INIT_COMM 19.8500 1311003.375 > 22 MPI_Init() 19.8500 1310925.750 > 33 RHS 18.4000 4690.500 > 8 EXCHANGE_3 9.2750 1179.000 > 26 MPI_Wait() 7.2250 565.125 > 13 JACLD 6.4875 27.000 > 25 MPI_Send() 6.3500 8.000 > 14 JACU 6.2500 26.000 > 37 SETIV 0.6625 20908.500 > 6 EXACT 0.2188 0.000 > 4 ERHS 0.2000 11499.000 > > Results for 32 machines > > Group.1 percent usec > 38 SSOR 97.28889 2573471.0000 > 7 EXCHANGE_1 39.25556 33.3333 > 2 BLTS 29.11111 98.7778 > 3 BUTS 27.96667 95.0000 > 24 MPI_Recv() 27.48889 28.7778 > 33 RHS 23.98889 5018.6667 > 25 MPI_Send() 13.51111 14.0000 > 8 EXCHANGE_3 13.06667 1361.1111 > 26 MPI_Wait() 9.37778 599.0000 > 13 JACLD 7.72222 26.0000 > 14 JACU 7.37778 25.0000 > 12 INIT_COMM 1.46667 76713.6667 > 22 MPI_Init() 1.45556 76253.4444 > 37 SETIV 0.80000 20914.0000 > 6 EXACT 0.25000 0.0000 > 4 ERHS 0.21111 10458.3333 > > The function MPI_init() in the first case (4 processes per machine) was 17 > times slower than the second case (1 process per machine). Is this behaviour > normal? > The command I used for running the application was: > > First case: > > mpirun --machinefile machine_file -npernode 4 --mca btl self,sm,tcp lu.A.32 > > Second case: > > mpirun --machinefile machine_file --mca btl self,sm,tcp lu.A.32 > > I used the version of mpi: > > mpirun --V > mpirun (Open MPI) 1.4.5 > > and the system I used is the following: > > Linux kameleon-debian 3.2.0-4-amd64 #1 SMP Debian 3.2.65-1+deb7u2 x86_64 > GNU/Linux > > I will appreciate any feedback, thank you. > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/04/26735.php
