FYI attached here OpenMPI install details On Wed, Oct 8, 2008 at 7:56 PM, Sangamesh B <forum....@gmail.com> wrote:
> > > On Wed, Oct 8, 2008 at 7:16 PM, Jeff Squyres <jsquy...@cisco.com> wrote: > >> On Oct 8, 2008, at 9:10 AM, Sangamesh B wrote: >> >> I wanted to switch from mpich2/mvapich2 to OpenMPI, as OpenMPI >>> supports both ethernet and infiniband. Before doing that I tested an >>> application 'GROMACS' to compare the performance of MPICH2 & OpenMPI. Both >>> have been compiled with GNU compilers. >>> >>> After this benchmark, I came to know that OpenMPI is slower than MPICH2. >>> >>> This benchmark is run on a AMD dual core, dual opteron processor. Both >>> have compiled with default configurations. >>> >>> The job is run on 2 nodes - 8 cores. >>> >>> OpenMPI - 25 m 39 s. >>> MPICH2 - 15 m 53 s. >>> >> >> >> A few things: >> >> - What version of Open MPI are you using? Please send the information >> listed here: >> > 1.2.7 > >> >> http://www.open-mpi.org/community/help/ >> >> - Did you specify to use mpi_leave_pinned? > > No > >> Use "--mca mpi_leave_pinned 1" on your mpirun command line (I don't know >> if leave pinned behavior benefits Gromacs or not, but it likely won't hurt) >> > >> - Did you enable processor affinity? > > No > >> Use "--mca mpi_paffinity_alone 1" on your mpirun command line. >> > Will use these options in the next benchmark > >> >> - Are you sure that Open MPI didn't fall back to ethernet (and not use >> IB)? Use "--mca btl openib,self" on your mpirun command line. >> > I'm using TCP. There is no infiniband support. But eventhough the results > can be compared? > >> >> - Have you tried compiling Open MPI with something other than GCC? > > No. > >> Just this week, we've gotten some reports from an OMPI member that they >> are sometimes seeing *huge* performance differences with OMPI compiled with >> GCC vs. any other compiler (Intel, PGI, Pathscale). We are working to >> figure out why; no root cause has been identified yet. >> > I'll try for other than gcc and comeback to you > >> >> -- >> Jeff Squyres >> Cisco Systems >> >> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users >> > > ***************************************************************************** ** ** ** WARNING: This email contains an attachment of a very suspicious type. ** ** You are urged NOT to open this attachment unless you are absolutely ** ** sure it is legitimate. Opening this attachment may cause irreparable ** ** damage to your computer and your files. If you have any questions ** ** about the validity of this message, PLEASE SEEK HELP BEFORE OPENING IT. ** ** ** ** This warning was added by the IU Computer Science Dept. mail scanner. ** *****************************************************************************
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