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Subject: Re: [OMPI devel] Return status of MPI_Probe()
From: Joshua Hursey (jjhursey_at_[hidden])
Date: 2011-03-22 10:46:31


Sounds good.

Would you mind reviewing the CMRs?
  https://svn.open-mpi.org/trac/ompi/ticket/2756
  https://svn.open-mpi.org/trac/ompi/ticket/2757

Thanks,
Josh

On Mar 22, 2011, at 10:19 AM, George Bosilca wrote:

> Josh,
>
> Your patch (r24551) looks fine. I think you should make a CMR for the 1.4 and 1.5.
>
> Thanks,
> george.
>
>
> On Mar 22, 2011, at 09:04 , Joshua Hursey wrote:
>
>> George,
>>
>> I agree that it is difficult to come up with a good scenario, outside of resilience, in which MPI_Probe would return an error (other than a bad argument type of error - which does currently work). I agree with your assessment of the value of the return code, and that it should trigger the error handler. I just wanted to confirm that there was not something I was missing.
>>
>> I will commit a patch to fix this (it is just a couple lines in pml/ob1) for the trunk. I don't know if we need to push it to the release branches just yet.
>>
>> Thanks,
>> Josh
>>
>> On Mar 21, 2011, at 10:17 PM, George Bosilca wrote:
>>
>>> Josh,
>>>
>>> If we don't take in account resilience I would not expect MPI_Probe to have that many opportunities to return errors. However, in order to keep the implementation consistent (with the other MPI functions) I would abide to the following.
>>>
>>> MPI_ERROR_IN_STATUS is only for calls taking multiple requests as input, so I don't think this should be applied to the MPI_Probe. I would expect the return to be equal to status.MPI_ERROR (similar to only other function working on a single request, such as MPI_Test).
>>>
>>> It better trigger the error-handler attached to the communicator, as explicitly requested by the MPI standard (section 8.3).
>>>> A user can associate error handlers to three types of objects: communicators, windows, and files. The specified error handling routine will be used for any MPI exception that occurs during a call to MPI for the respective object.
>>>
>>> george.
>>>
>>> On Mar 21, 2011, at 16:50 , Joshua Hursey wrote:
>>>
>>>> If MPI_Probe() encounters an error causing it to exit with the 'status.MPI_ERROR' set, say:
>>>> ret = MPI_Probe(MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
>>>>
>>>> Should it return an error? So should it return:
>>>> - ret = status.MPI_ERROR
>>>> - ret = MPI_ERROR_IN_STATUS
>>>> - ret = MPI_SUCCESS
>>>> Additionally, should it trigger the error handler on the communicator?
>>>>
>>>> In Open MPI, it will always return MPI_SUCCESS (pml_ob1_iprobe.c:74), but it feels like this is wrong. I looked to the MPI standard for some insight, but could not find where it addresses the return code of MPI_Probe.
>>>>
>>>> Can anyone shed some light on this topic for me?
>>>>
>>>> Thanks,
>>>> Josh
>>>>
>>>>
>>>> ------------------------------------
>>>> Joshua Hursey
>>>> Postdoctoral Research Associate
>>>> Oak Ridge National Laboratory
>>>> http://users.nccs.gov/~jjhursey
>>>>
>>>>
>>>> _______________________________________________
>>>> devel mailing list
>>>> devel_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>
>>> "To preserve the freedom of the human mind then and freedom of the press, every spirit should be ready to devote itself to martyrdom; for as long as we may think as we will, and speak as we think, the condition of man will proceed in improvement."
>>> -- Thomas Jefferson, 1799
>>>
>>>
>>> _______________________________________________
>>> devel mailing list
>>> devel_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>
>>
>> ------------------------------------
>> Joshua Hursey
>> Postdoctoral Research Associate
>> Oak Ridge National Laboratory
>> http://users.nccs.gov/~jjhursey
>>
>>
>> _______________________________________________
>> devel mailing list
>> devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>
> "To preserve the freedom of the human mind then and freedom of the press, every spirit should be ready to devote itself to martyrdom; for as long as we may think as we will, and speak as we think, the condition of man will proceed in improvement."
> -- Thomas Jefferson, 1799
>
>
> _______________________________________________
> devel mailing list
> devel_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>

------------------------------------
Joshua Hursey
Postdoctoral Research Associate
Oak Ridge National Laboratory
http://users.nccs.gov/~jjhursey