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From: Jeff Pummill (jpummil_at_[hidden])
Date: 2007-10-26 11:57:03


So, it appears that for a machine of this type (dual quad core cpu's),
this approach would be correct for my tests...

[jpummill_at_n1 bin]$ more my-hosts
n1 slots=8 max_slots=8

and subsequently, launch two jobs in this configuration...
/home/jpummill/openmpi-1.2.2/bin/mpirun --hostfile my-hosts -np 4
--byslot ./cg.C.4

It appears that this does avoid oversubscribing any particular core as I
am not exceeding my core count by running just the two jobs requiring 4
cores each.

Thanks,

Jeff Pummill

George Bosilca wrote:
> The cleaner way to define such an environment is by using the
> max-slots and/or slots options in the hostfile. Here is a FAQ entry
> about how Open MPI deal with these options
> (http://www.open-mpi.org/faq/?category=running#mpirun-scheduling).
>
> george.
>
>
> On Oct 26, 2007, at 10:52 AM, Jeff Pummill wrote:
>
>> I am doing some testing on a variety of 8-core nodes in which I just
>> want to execute a couple of executables and have them distributed to
>> the available cores without overlapping. Typically, this would be
>> done with a parameter like -machinefile machines, but I have no idea
>> what names to put into the machines file as this is a single node
>> with two quad core cpu's. As I am launching the jobs sans scheduler,
>> I need to specify what cores to run on I would think to keep from
>> overscheduling some cores while others receive nothing to do at all.
>>
>> Simple suggestions? Maybe Open MPI takes care of this detail for me?
>>
>> Thanks!
>>
>> Jeff Pummill
>> _______________________________________________
>> users mailing list
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