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Subject: Re: [OMPI users] How do I run OpenMPI safely on a Nehalem standalone machine?
From: Ralph Castain (rhc_at_[hidden])
Date: 2010-05-06 10:02:10


Yo Gus

Just saw a ticket go by reminding us about continuing hang problems on shared memory when building with gcc 4.4.x - any chance you are in that category? You might have said something earlier in this thread....

On May 5, 2010, at 5:54 PM, Douglas Guptill wrote:

> On Wed, May 05, 2010 at 06:08:57PM -0400, Gus Correa wrote:
>
>> If anybody else has Open MPI working with hyperthreading and "sm"
>> on a Nehalem box, I would appreciate any information about the
>> Linux distro and kernel version being used.
>
> Debian 5 (lenny), Core i7 920, Asus P6T MoBo, 12GB RAM, OpenMPI 1.2.8
> (with a custom-built MPI_recv.c and MPI_Send.c, which cut down on the
> cpu load caused by the busy wait polling). We have six (6) of these
> machines. All configured the same.
>
> uname -a yields:
> Linux screm 2.6.26-2-amd64 #1 SMP Thu Feb 11 00:59:32 UTC 2010 x86_64 GNU/Linux
>
> HyperThreading is on.
>
> Applications are -np 2 only:
> mpirun --host localhost,localhost --byslot --mca btl sm,self -np 2 ${BIN}
>
> We normally run (up to) 4 of these jobs on each machine.
>
> Using Intel 11.0.074 and 11.1.0** compilers; have trouble with the
> 11.1.0** and "-mcmodel=large -shared-intel" builds. Trouble meaning
> the numerical results vary strangely. Still working on that problem.
>
> Hope that helps,
> Douglas.
>
> P.S. Yes, I know OpenMPI 1.2.8 is old. We have been using it for 2
> years with no apparent problems. When I saw comments like "machine
> hung" for 1.4.1, and "data loss" for 1.3.x, I put aside thoughts of
> upgrading.
>
> --
> Douglas Guptill voice: 902-461-9749
> Research Assistant, LSC 4640 email: douglas.guptill_at_[hidden]
> Oceanography Department fax: 902-494-3877
> Dalhousie University
> Halifax, NS, B3H 4J1, Canada
>
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