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From: Ralph H Castain (rhc_at_[hidden])
Date: 2007-02-13 14:20:14


On 2/13/07 11:30 AM, "Brock Palen" <brockp_at_[hidden]> wrote:

> On Feb 13, 2007, at 12:55 PM, Troy Telford wrote:
>
>> First, the good news:
>> I've recently tried PBS Pro 8 with Open MPI 1.1.4.
>>
>> At least with PBS Pro version 8, you can (finally) do a dynamic/shared
>> object for the TM module, rather than having to compile everything
>> statically. (So the FAQ needs a minor update.) The jobs seem to
>> run and
>> use TM properly.
>
> Good,
>
>>
>> The bad news:
>> My memory is a bit fuzzy on how to use OMPI with PBS and cousins.
>> Sad, I
>> know, but that doesn't make it any less true.
>
> Make sure your OMPI build used --with-tm=/path/to/pbs
>
> You can also use ompi_info and grep for tm.
>
>>
>> For the moment, I've read the FAQ and see that you need to use the
>> '-np
>> <foo>' option to specify the number of processes. For some reason, I
>> recall that OMPI used to be able to get the number of processes to run
>> from PBS; am I just 'remembering' something that never existed?
>
> To my memory this has never been the case. there is $PBS_NODEFILE
> which you can wrap around:
>
> CPUS=`cat $PBS_NODEFILE | wc -l`
>
> mpirun -np $CPUS myexe

Actually, that isn't the complete story. Open MPI will automatically run in
several ways:

1. one proc in each available slot on every node in your allocation: just
don't include -np on your command line. You can rank them by slot (--byslot
or leave out) or by node (--bynode).

2. one proc on each node in your allocation: use --pernode on your command
line. You can limit the number of nodes used by combining --pernode with -np
<foo> - we will launch <foo> procs, one per node

3. a specified number of procs on every node: use --npernode <n>. Again, you
can limit the number of procs launched by combining it with -np and can rank
by slot or node

Ralph

>
>> --
>> Troy Telford
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>
>
>
> Brock Palen
> Center for Advanced Computing
> brockp_at_[hidden]
> (734)936-1985
>
>
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