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Subject: Re: [OMPI users] User Interface for MPMD
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2012-08-10 16:45:50


I swear that there was an MPI-3 proposal for just about exactly this issue (because there is currently no MPI-standardized way to get this information).

I honestly don't remember what happened to this proposal, but I know who made it (Adam Moody, from Livermore). I've just pinged him off list to find out what happened to that proposal.

Stay tuned...

On Aug 10, 2012, at 1:50 PM, Frank Kampe wrote:

> OK. I think I am not being clear and am using the wrong terms. For example, suppose we launch and MPMD job:
>
> mpirun -np 1 a.out : -np 8 a.out2 : -np 512 a.out3
>
> There are three "instances" invoked here---that's info item(1). In other words, how many executables are started. Given MPMD mode, the entire set of apps belong to the same MPI_COMM_WORLD. So, MPI Task 0 is the MPI rank of the process executing a.out, MPI Task 1 is the 1st MPI rank for process(s) executing a.out2, and Task 9 is the 1st MPI rank for processes(s) executing a.out3. That's the info in item (2) below. Finally number of tasks for instance 1 is 1, for instance 2 is 8, and for instance 3 is 512---that's item (3).
>
> What user-callable interface does OpenMPI provide to get that information in a.out, a.out2, and a.out3 during run-time?
>
> Thanks.
>
> ________________________________________
> From: users-bounces_at_[hidden] [users-bounces_at_[hidden]] on behalf of Ralph Castain [rhc_at_[hidden]]
> Sent: Friday, August 10, 2012 12:00 PM
> To: Open MPI Users
> Subject: Re: [OMPI users] User Interface for MPMD
>
> I gather you don't want to use the MPI calls to get it? Perhaps it would help if we understood a little more about what you are trying to do.
>
> Or maybe we just aren't understanding the term "instance" - e.g., for #1, you want to know how many processes are executing in the job, yes?
>
> If that's correct, then the second question doesn't make sense to me - so I'm a little lost.
>
>
> On Aug 10, 2012, at 9:49 AM, Frank Kampe <u2591_at_[hidden]> wrote:
>
>> No. I am looking for a user-callable function that will return information about the running OpenMPI MPMD program from within the running program---the information listed below in (1) -- (3).
>>
>> ________________________________________
>> From: users-bounces_at_[hidden] [users-bounces_at_[hidden]] on behalf of Ralph Castain [rhc_at_[hidden]]
>> Sent: Friday, August 10, 2012 11:15 AM
>> To: Open MPI Users
>> Subject: Re: [OMPI users] User Interface for MPMD
>>
>> I'm actually not sure I understand the question - are you talking about a programmatic API where an application wants to spawn an MPI program? Or an inter-program communication API that wants to tell another program some information? Or an API by which the app can tell MPI "I'm going to spawn N threads"? Or...?
>>
>>
>> On Aug 10, 2012, at 9:00 AM, Gus Correa <gus_at_[hidden]> wrote:
>>
>>> On 08/10/2012 11:31 AM, Frank Kampe wrote:
>>>> Are there any user level APIs to provide the following information to a running OpenMPI MPMD program:
>>>>
>>>> (1) Number of executable instances
>>>>
>>>> (2) 1st MPI Task rank of each instance
>>>>
>>>> (3) Number of MPI Tasks per instance
>>>>
>>>> Thank You
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> users mailing list
>>>> users_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>> Hi Frank
>>> Check 'man mpiexec', the --app file option, maybe also --rankfile.
>>> The on process binding at the end may also help.
>>> I hope this helps,
>>> Gus Correa
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
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>
>
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-- 
Jeff Squyres
jsquyres_at_[hidden]
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