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Subject: Re: [OMPI users] How to specify hosts for MPI_Comm_spawn
From: Mark Borgerding (markb_at_[hidden])
Date: 2008-07-28 11:14:29

Thanks, I don't know how I missed that. Perhaps I got thrown off by
    "Portable programs not requiring detailed control over process
locations should use MPI_INFO_NULL."

If there were a computing equivalent of Maslow's Hierarchy of Needs,
functioning would be more fundamental than portability :)

-- Mark

Ralph Castain wrote:
> Take a look at the man page for MPI_Comm_spawn. It should explain that
> you need to create an MPI_Info key that has the key of "host" and a
> value that contains a comma-delimited list of hosts to be used for the
> child processes.
> Hope that helps
> Ralph
> On Jul 28, 2008, at 8:54 AM, Mark Borgerding wrote:
>> How does openmpi decide which hosts are used with MPI_Comm_spawn? All
>> the docs I've found talk about specifying hosts on the mpiexec/mpirun
>> command and so are not applicable.
>> I am unable to spawn on anything but localhost (which makes for a
>> pretty uninteresting cluster).
>> When I run
>> ompi_info --param rds hostfile
>> It reports MCA rds: parameter "rds_hostfile_path"
>> (current value:
>> "/usr/lib/openmpi/1.2.5-gcc/etc/openmpi-default-hostfile")
>> I tried changing that file but it has no effect.
>> I am using
>> openmpi 1.2.5
>> CentOS 5.2
>> ethernet TCP
>> -- Mark
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]
> _______________________________________________
> users mailing list
> users_at_[hidden]

Mark Borgerding
3dB Labs, Inc
Innovate.  Develop.  Deliver.