Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: Re: [OMPI users] Performance: MPICH2 vs OpenMPI
From: Samuel Sarholz (sarholz_at_[hidden])
Date: 2008-10-08 09:47:49


my experience is that OpenMPI has slightly less latency and less
bandwidth than Intel MPI (which is based on mpich2) using InfiniBand.
I don't remember the numbers using shared memory.

As you are seeing a huge difference, I would suspect that either
something with your compilation is strange or more probable that you hit
the cc-numa effect of the Opteron.
You might want to bind the MPI processes (and even clean the filesystem
caches) to avoid that effect.

best regards,

Sangamesh B wrote:
> Hi All,
> 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.
> Any comments ..?
> Thanks,
> Sangamesh