Hello Gilles,
Ok, I believe I have a simple toy app running as I think it should:
'n' parent processes running under mpi_comm_world, each one
spawning its own 'm' child processes (each child group work
together nicely, returning the expected result for an mpi_allreduce call).
Now, as I mentioned before, the apps I want to run in the spawned
processes are third party mpi apps and I don't think it will be possible
to exchange messages with them from my app. So, I do I tell
when the spawned processes have finnished running? All I have to work
with is the intercommunicator returned from the mpi_comm_spawn call...
Alex
2014-12-12 2:42 GMT-02:00 Alex A. Schmidt <a...@ufsm.br>:
>
> Gilles,
>
> Well, yes, I guess....
>
> I'll do tests with the real third party apps and let you know.
> These are huge quantum chemistry codes (dftb+, siesta and Gaussian)
> which greatly benefits from a parallel environment. My code is just
> a front end to use those, but since we have a lot of data to process
> it also benefits from a parallel environment.
>
> Alex
>
>
> 2014-12-12 2:30 GMT-02:00 Gilles Gouaillardet <
> gilles.gouaillar...@iferc.org>:
>>
>> Alex,
>>
>> just to make sure ...
>> this is the behavior you expected, right ?
>>
>> Cheers,
>>
>> Gilles
>>
>>
>> On 2014/12/12 13:27, Alex A. Schmidt wrote:
>>
>> Gilles,
>>
>> Ok, very nice!
>>
>> When I excute
>>
>> do rank=1,3
>> call MPI_Comm_spawn('hello_world','
>> ',5,MPI_INFO_NULL,rank,MPI_COMM_WORLD,my_intercomm,MPI_ERRCODES_IGNORE,status)
>> enddo
>>
>> I do get 15 instances of the 'hello_world' app running: 5 for each parent
>> rank 1, 2 and 3.
>>
>> Thanks a lot, Gilles.
>>
>> Best regargs,
>>
>> Alex
>>
>>
>>
>>
>> 2014-12-12 1:32 GMT-02:00 Gilles Gouaillardet <gilles.gouaillar...@iferc.org
>>
>> :
>>
>> Alex,
>>
>> just ask MPI_Comm_spawn to start (up to) 5 tasks via the maxprocs
>> parameter :
>>
>> int MPI_Comm_spawn(char *command, char *argv[], int maxprocs,
>> MPI_Info info,
>> int root, MPI_Comm comm, MPI_Comm *intercomm,
>> int array_of_errcodes[])
>>
>> INPUT PARAMETERS
>> maxprocs
>> - maximum number of processes to start (integer, significant
>> only at root)
>>
>> Cheers,
>>
>> Gilles
>>
>>
>> On 2014/12/12 12:23, Alex A. Schmidt wrote:
>>
>> Hello Gilles,
>>
>> Thanks for your reply. The "env -i PATH=..." stuff seems to work!!!
>>
>> call system("sh -c 'env -i PATH=/usr/lib64/openmpi/bin:/bin mpirun -n 2
>> hello_world' ")
>>
>> did produce the expected result with a simple openmi "hello_world" code I
>> wrote.
>>
>> I might be harder though with the real third party app I have in mind. And
>> I realize
>> getting passed over a job scheduler with this approach might not work at
>> all...
>>
>> I have looked at the MPI_Comm_spawn call but I failed to understand how it
>> could help here. For instance, can I use it to launch an mpi app with the
>> option "-n 5" ?
>>
>> Alex
>>
>> 2014-12-12 0:36 GMT-02:00 Gilles Gouaillardet <gilles.gouaillar...@iferc.org
>>
>>
>> :
>>
>> Alex,
>>
>> can you try something like
>> call system(sh -c 'env -i /.../mpirun -np 2 /.../app_name')
>>
>> -i start with an empty environment
>> that being said, you might need to set a few environment variables
>> manually :
>> env -i PATH=/bin ...
>>
>> and that being also said, this "trick" could be just a bad idea :
>> you might be using a scheduler, and if you empty the environment, the
>> scheduler
>> will not be aware of the "inside" run.
>>
>> on top of that, invoking system might fail depending on the interconnect
>> you use.
>>
>> Bottom line, i believe Ralph's reply is still valid, even if five years
>> have passed :
>> changing your workflow, or using MPI_Comm_spawn is a much better approach.
>>
>> Cheers,
>>
>> Gilles
>>
>> On 2014/12/12 11:22, Alex A. Schmidt wrote:
>>
>> Dear OpenMPI users,
>>
>> Regarding to this previous
>> post<http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
>> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
>> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
>> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
>> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
>> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
>> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
>> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php> from 2009,
>> I wonder if the reply
>> from Ralph Castain is still valid. My need is similar but quite simpler:
>> to make a system call from an openmpi fortran application to run a
>> third party openmpi application. I don't need to exchange mpi messages
>> with the application. I just need to read the resulting output file
>> generated
>> by it. I have tried to do the following system call from my fortran openmpi
>> code:
>>
>> call system("sh -c 'mpirun -n 2 app_name")
>>
>> but I get
>>
>> **********************************************************
>>
>> Open MPI does not support recursive calls of mpirun
>>
>> **********************************************************
>>
>> Is there a way to make this work?
>>
>> Best regards,
>>
>> Alex
>>
>>
>>
>>
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