Did you tell it --bind-to-core? If not, then the procs would be unbound to any particular core - so your code might well think they are "sharing" cores.
On Apr 24, 2012, at 4:46 PM, Kyle Boe wrote: > 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-requ...@open-mpi.org> wrote: > From: Ralph Castain <r...@open-mpi.org> > Subject: Re: [OMPI users] MPI doesn't recognize multiple cores > available on multicore machines > To: Open MPI Users <us...@open-mpi.org> > Message-ID: <f9d4fce5-9974-4814-9bcf-a39124961...@open-mpi.org> > 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? > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
