Jeff, Yes, I would be interested in such a plugin. But be advised that I am strictly a fortran programmer, so if it requires any C/C++ talent, I would be in trouble. So maybe, before jumping into that, I would like to be able to look at what processor/node mapping Open-mpi is actually giving me. Is there an environmental variable or an MCA option I can add to my 'mpirun' command line that would give that to me? I am running 1.5.4.
T. Rosmond On Tue, 2012-04-24 at 15:11 -0400, Jeffrey Squyres wrote: > On Apr 24, 2012, at 3:01 PM, Tom Rosmond wrote: > > > My question is this: If the cartesian mapping is done so the two > > spacial dimensions are the 'most rapidly varying' in equivalent 1-D > > processor mapping, will Open-mpi automatically assign those 2 dimensions > > 'on-node', and assign the 'ensemble' dimension as the slowest varying > > and across nodes? If not, how can we guarantee this to happen? > > > Sadly, the MPI mapping functions in Open MPI are effectively no-ops -- if you > ask for re-ordering, OMPI says "sure!" but then gives you back exactly the > same mapping. :-( > > That being said, the mapping functionality is actually a plugin in Open MPI > (in the "topo" framework). It would not be too difficult to write a plugin > for the mapping that you want. > > Would this be of interest to you? I'd be happy to talk you through the > process of writing such a plugin. >
