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Subject: Re: [OMPI users] MPI doesn't recognize multiple cores available on multicore machines
From: Kyle Boe (boex0040_at_[hidden])
Date: 2012-04-24 18:46:59


Right, I tried using a hostfile, and it made no difference. This is running
OpenMPI 1.4.4 on CentOS 5.x machines. The original issue was an error trap
built into my code, where it said one of the cores was asking for
information it already owned. I'm sorry to be vague, but I can't share
anything from the code in this forum. Basically, it is a CFD code,
parallelized by splitting the grid points in the simulation up amongst the
processors assigned to the job. As a pre-processing step, each processor
must figure out which other processors it must communicate with by virtue
of sharing neighboring gridpoints. The error I received told me that the
grid points were not being split amongst different processors. I have used
this exact same code using OpenMPI on other (larger) architectures, which,
combined with the MPI error I shared before, leads me to believe I must
have something not configured correctly, or there is some run time option
I'm not setting properly, etc.

Thanks

Kyle

On Tue, Apr 24, 2012 at 4:15 PM, <users-request_at_[hidden]> wrote:

> From: Ralph Castain <rhc_at_[hidden]>
> Subject: Re: [OMPI users] MPI doesn't recognize multiple cores
> available on multicore machines
> To: Open MPI Users <users_at_[hidden]>
> Message-ID: <F9D4FCE5-9974-4814-9BCF-A39124961B32_at_[hidden]>
> Content-Type: text/plain; charset=us-ascii
>
> You don't need a hostfile to run multiple procs on the localhost.
>
> What version of OMPI are you using? What was the original issue?
>
>