Any thoughts on this?
We are looking writing a script that parses $PBS_NODEFILE to create a
machinefile and using -machinefile
When we do that though we have to disable tm to avoid an error (-mca
pls ^tm) this is far from preferable.
Any ideas to tell mpirun to only launch on half the cpus given to it
by PBS, but each cpu must have adjacent to it another cpu in the same
node?
Brock Palen
www.umich.edu/~brockp
Center for Advanced Computing
bro...@umich.edu
(734)936-1985
On Oct 25, 2008, at 5:36 PM, Brock Palen wrote:
We have a user with a code that uses threaded solvers inside each
MPI rank. They would like to run two threads per process.
The question is how to launch this? The default -byslot puts all
the processes on the first sets of cpus not leaving any cpus for
the second thread for each process. And half the cpus are wasted.
The -bynode option works in theory, if all our nodes had the same
number of core (they do not).
So right now the user did:
#PBS -l nodes=22:ppn=2
export OMP_NUM_THREADS=2
mpirun -np 22 app
Which made me aware of the problem.
How can I basically tell OMPI that a 'slot' is two cores on the
same machine? This needs to work inside out torque based
queueing system.
Sorry If I was not clear about my goal.
Brock Palen
www.umich.edu/~brockp
Center for Advanced Computing
bro...@umich.edu
(734)936-1985
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