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Subject: Re: [OMPI users] MPI_Comm_spawn and oreted
From: Ralph Castain (rhc_at_[hidden])
Date: 2009-04-16 10:44:53


The orteds don't pass anything from MPI_Info to srun during a
comm_spawn. What the orteds do is to chdir to the specified wdir
before spawning the child process to ensure that the child has the
correct working directory, then the orted changes back to its default
working directory.

The orted working directory is set by the base environment. So your
slurm arguments cause *all* orteds to use the specified directory as
their "home base". They will then use any given wdir keyval when they
launch their respective child processes, as described above.

As a side note, it isn't clear to me why you care about the orted's
working directory. The orteds don't write anything there, or do
anything with respect to their "home base" - so why would this matter?
Or are you trying to specify the executable's path relative to where
the orted is sitting?

On Apr 16, 2009, at 4:02 AM, Jerome BENOIT wrote:

> Hi !
>
> finally I got it:
> passing the mca key/value `"plm_slurm_args"/"--chdir /local/folder"'
> does the trick.
>
> As a matter of fact, my code pass the MPI_Info key/value `"wdir"/"/
> local/folder"'
> to MPI_Comm_spawn as well: the working directories on the nodes of
> the spawned programs
> are `nodes:/local/folder' as expected, but the working directory of
> the oreted_s
> is the working directory of the parent program. My guess is that the
> MPI_Info key/vale
> may also be passed to `srun'.
>
> hth,
> Jerome
>
>
>
> Jerome BENOIT wrote:
>> Hello Again,
>> Jerome BENOIT wrote:
>>> Hello List,
>>>
>>> I have just noticed that, when MPI_Comm_spawn is used to launch
>>> programs around,
>>> oreted working directory on the nodes is the working directory of
>>> the spawnning program:
>>> can we ask to oreted to use an another directory ?
>> Changing the working the directory via chdir before spawning with
>> MPI_Comm_spawn
>> changes nothing: the oreted working directory on the nodes seems to
>> be imposed
>> by something else. As run OMPI on top of SLURM, I guess this is
>> related to SLURM.
>> Jerome
>>>
>>> Thanks in advance,
>>> Jerome _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>
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