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Subject: Re: [OMPI users] MPI_Test bug?
From: jody (jody.xha_at_[hidden])
Date: 2009-02-05 08:31:51


I have to admit, that this wasn't a theoretically well founded suggestion.
Perhaps it really doesn't (or shouldn't) matter...
I'll try both versions with MPI 1.3 and tell you the results

Jody

On Thu, Feb 5, 2009 at 11:48 AM, Gabriele Fatigati <g.fatigati_at_[hidden]> wrote:
> Hi Jody,
> thanks four your quick reply. But what's the difference?
>
> 2009/2/5 jody <jody.xha_at_[hidden]>:
>> Hi Gabriele
>>
>> Shouldn't you reverse the order of your send and recv from
>> MPI_Irecv(buffer_recv, bufferLen, MPI_INT, recv_to, tag,
>> MPI_COMM_WORLD, &request);
>> MPI_Send(buffer_send, bufferLen, MPI_INT, send_to, tag, MPI_COMM_WORLD);
>>
>> to
>>
>> MPI_Send(buffer_send, bufferLen, MPI_INT, send_to, tag, MPI_COMM_WORLD);
>> MPI_Irecv(buffer_recv, bufferLen, MPI_INT, recv_to, tag,
>> MPI_COMM_WORLD, &request);
>>
>> ?
>> Jody
>>
>> On Thu, Feb 5, 2009 at 11:37 AM, Gabriele Fatigati <g.fatigati_at_[hidden]> wrote:
>>> Dear OpenMPI developer,
>>> i have found a very strange behaviour of MPI_Test. I'm using OpenMPI
>>> 1.2 over Infiniband interconnection net.
>>>
>>> I've tried to implement net check with a series of MPI_Irecv and
>>> MPI_Send beetwen processors, testing with MPI_Wait the end of Irecv.
>>> For strange reasons, i've noted that, when i launch the test in one
>>> node, it works well. If i launch over 2 or more procs over different
>>> nodes, MPI_Test fails many time before to tell that the IRecv is
>>> finished.
>>>
>>> I've tried that it fails also after one minutes, with very small
>>> buffer( less than eager limit). It's impossible that the communication
>>> is pending after one minutes, with 10 integer sended. To solve this,
>>> I need to implement a loop over MPI_Test, and only after 3 or 4
>>> MPI_Test it returns that IRecv finished successful. Is it possible
>>> that MPI_Test needs to call many time also if the communication is
>>> already finished?
>>>
>>> In attach you have my simple C test program.
>>>
>>> Thanks in advance.
>>>
>>> --
>>> Ing. Gabriele Fatigati
>>>
>>> Parallel programmer
>>>
>>> CINECA Systems & Tecnologies Department
>>>
>>> Supercomputing Group
>>>
>>> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
>>>
>>> www.cineca.it Tel: +39 051 6171722
>>>
>>> g.fatigati [AT] cineca.it
>>>
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>
>
>
> --
> Ing. Gabriele Fatigati
>
> Parallel programmer
>
> CINECA Systems & Tecnologies Department
>
> Supercomputing Group
>
> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
>
> www.cineca.it Tel: +39 051 6171722
>
> g.fatigati [AT] cineca.it
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>