Hmmm...your comments don't sound like anything relating to Open MPI.
Are you sure you are not using some other MPI?
Our mpiexec isn't a script, for example, nor do we have anything named
I_MPI_PIN_PROCESSOR_LIST in our code.
:-)
On Mar 13, 2009, at 4:00 AM, Peter Teoh wrote:
I saw the following problem posed somewhere - can anyone shed some
light? Thanks.
I have a cluster of 8-sock quad core systems running Redhat 5.2. It
seems that whenever I try to run multiple MPI jobs to a single node
all the jobs end up running on the same processors. For example, if I
were to submit 4 8-way jobs to a single box they all end up in CPUs 0
to 7, leaving 8 to 31 idle.
I then tried all sorts of I_MPI_PIN_PROCESSOR_LIST combinations but
short of explicitly listing out the processors at each run, they all
end up still hanging on to CPUs 0-7. Browsing through the mpiexec
script, I realise that it is doing a taskset on each run.
As my jobs are all submitted through a scheduler (PBS in this case) I
cannot possibly know at job submission time which CPUs are not used.
So is there a simple way to tell mpiexec to set the taskset affinity
correctly at each run so that it will choose only the idle processors?
Thanks.
--
Regards,
Peter Teoh
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