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Subject: Re: [OMPI users] 50% performance reduction due to OpenMPI v 1.3.2 forcing all MPI traffic over Ethernet instead of using Infiniband
From: Jim Kress ORG (jimkress_58_at_[hidden])
Date: 2009-06-23 17:42:06


Sorry about the size of the last email. I wasn't aware the log file
would be so lagre ...

Jim

On Tue, 2009-06-23 at 15:20 -0600, Ralph Castain wrote:
> Hmmm...just to be clear - did you run this against OMPI 1.3.2, or
> 1.2.8? I see a 1.2.8 in your app name, hence the question.
>
> This option only works with 1.3.2, I'm afraid - it was a new feature.
>
> Ralph
>
> On Jun 23, 2009, at 2:31 PM, Jim Kress ORG wrote:
>
> > Ralph,
> >
> > I did the following:
> >
> > export OMPI_MCA_mpi_show_mca_params="file,env"
> >
> > then I checked and found it via the set command as
> >
> > OMPI_MCA_mpi_show_mca_params=file,env
> >
> > I then ran my application
> >
> > ./orca hexatriene_TDDFT_get_asa_input_parallel_1.inp >
> > 1.2.8_test_crafted_input_file.out
> >
> > and got the expected ORCA output in the .out file but nothing at the
> > command line or in the .out file about mca_params
> >
> > What did I do wrong?
> >
> > Jim
> >
> > On Mon, 2009-06-22 at 19:40 -0600, Ralph Castain wrote:
> >> Sounds very strange, indeed. You might want to check that your app is
> >> actually getting the MCA param that you think it is. Try adding:
> >>
> >> -mca mpi_show_mca_params file,env
> >>
> >> to your cmd line. This will cause rank=0 to output the MCA params it
> >> thinks were set via the default files and/or environment (including
> >> cmd line).
> >>
> >> Ralph
> >>
> >> On Jun 22, 2009, at 6:14 PM, Jim Kress ORG wrote:
> >>
> >>> For the app I am using, ORCA (a Quantum Chemistry program), when it
> >>> was
> >>> compiled using openMPI 1.2.8 and run under 1.2.8 with the
> >>> following in
> >>> the openmpi-mca-params.conf file:
> >>>
> >>> btl=self,openib
> >>>
> >>> the app ran fine with no traffic over my Ethernet network and all
> >>> traffic over my Infiniband network.
> >>>
> >>> However, now that ORCA has been recompiled with openMPI v1.3.2 and
> >>> run
> >>> under 1.3.2 (using the same openmpi-mca-params.conf file), the
> >>> performance has been reduced by 50% and all the MPI traffic is going
> >>> over the Ethernet network.
> >>>
> >>> As a matter of fact, the openMPI v1.3.2 performance now looks
> >>> exactly
> >>> like the performance I get if I use MPICH 1.2.7.
> >>>
> >>> Anyone have any ideas:
> >>>
> >>> 1) How could this have happened?
> >>>
> >>> 2) How can I fix it?
> >>>
> >>> a 50% reduction in performance is just not acceptable. Ideas/
> >>> suggestions would be appreciated.
> >>>
> >>> Jim
> >>>
> >>> _______________________________________________
> >>> users mailing list
> >>> users_at_[hidden]
> >>> http://www.open-mpi.org/mailman/listinfo.cgi/users
> >>
> >> _______________________________________________
> >> users mailing list
> >> users_at_[hidden]
> >> http://www.open-mpi.org/mailman/listinfo.cgi/users
> >
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