[mpich-discuss] MPI_Comm_spawn / MPI_Info question

[Pavan Balaji]

Hydra does respect the "hosts" environment variable.  However, it might 
have been added after 1.4.1p1 was released.  You can pick the 1.5rc1 
release of Hydra and use it with mpich2-1.4.1p1 (it's backward compatible).

Note that "host" is a part of the MPI standard, while "hosts" is not. 
So you'll be using a Hydra-specific option.

  -- Pavan

On 09/16/2012 07:18 PM, Christoph Sprenger wrote:
>
> doh accidently pressed ctrl-enter.
>
> it seems that hydra passes envall by default to spawned nodes which
> solves pretty much my previous issue.
>
> i am trying to figure out if its possible to do the following:
> MPI_Info_set(info, "hosts", "node1,node2");
>
> seems that they all get launched on the original node where mpiexec was run.
>
> MPI_Info_set(info, "host", "node2");
> seems to work fine and it spawns as expected on the other machine.
> preferably i wanted to avoid generating a hostfile and was curious if
> thats possible to supply multiple machines directly in the MPI_Info.
>
> Cheers,
> Christoph
>
>
>
>
> On 17/09/12 12:06, Christoph Sprenger wrote:
>>
>> Thanks for that Pavan.
>> Just installed and upgraded and super happy how smooth that went.
>>
>>
>>
>>
>> On 16/09/12 17:19, Pavan Balaji wrote:
>>>
>>> Can you upgrade to the latest version of mpich2?  1.2.1p1 is too old;
>>> it uses a different process manager which is not supported anymore.
>>>
>>>   -- Pavan
>>>
>>> On 09/15/2012 09:23 PM, Christoph Sprenger wrote:
>>>> Hi,
>>>>
>>>> I've been trying to get MPI_Info to work with the Spawn interface, but
>>>> seems like the env vars aren't supplied to the new processes.
>>>> I've been searching the docs and source, but can't find the list of
>>>> hints for mpich2, so i am not sure if "envlist" is the right key for
>>>> the
>>>> mpd.
>>>> not sure if i missed the obvious. is there an overview somewhere of all
>>>> the reserved keys ( eg envall,... )
>>>>
>>>>
>>>>
>>>> MPI_Info info;
>>>> MPI_Info_create(&info);
>>>> MPI_Info_set(info, "envlist", "CUSTOM_VAR");
>>>>
>>>> ...
>>>> MPI_Comm_spawn(argv[0], &argv[1] , n, info, 0, MPI_COMM_WORLD,
>>>> &intracomm, MPI_ERRCODES_IGNORE);
>>>>
>>>>
>>>> i currently use mpich2-1.2.1
>>>>
>>>>
>>>> Cheers,
>>>> Christoph
>>>>
>>>>
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>>>
>>
>

-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji