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From: Tim Prins (tprins_at_[hidden])
Date: 2007-06-06 17:23:33


Note that since you are setting OMPI_MCA_pml to cm, OMPI_MCA_btl will have no
effect. You may try setting OMPI_MCA_pml=ob1, and trying your measurements
again, but we generally get better performance with the cm pml than then ob1
pml.

Tim

On Wednesday 06 June 2007 12:54:26 pm George Bosilca wrote:
> Which one is the latency with Open MPI ? Which version of Open MPI ?
>
> You might want to use OMPI_MCA_btl=mx,self to see if it makes any
> difference.
>
> Thanks,
> george.
>
> On Jun 6, 2007, at 12:26 PM, Maestas, Christopher Daniel wrote:
> > With 2 nodes using 1.1.7 with the patch we measured (using mpich-mx
> > 1.2.7..4):
> > 3.07us
> >
> > With mx 1.2.1-rc18 we measure:
> > 3.69 us
> > And with mpich-mx 1.2.7..4 we see:
> > 3.20us
> >
> > Our Open MPI settings:
> > ---
> > # env | grep OMPI
> > OMPI_MCA_pml=cm
> > OMPI_MCA_mpi_keep_hostnames=1
> > OMPI_MCA_oob_tcp_include=eth0
> > OMPI_MCA_btl=mx,sm,self
> >
> > Does anyone know why the latency would be slightly higher using
> > Open MPI
> > versus MPICH-MX?
> >
> > Thanks,
> > -cdm
> >
> >
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