[Mpi-forum] MPI_WAIT/MPI_TEST and generalized, I/O, and NBC requests

[Fab Tillier]

Non-blocking I/O requests weren't covered by the text in the 2.2 standard, so it's not just generalized requests that were missed.  Other than that, you have it correct Rolf.  I would word it slightly differently, though, something  along the lines of:

"If the operation associated with this request was a persistent communication operation, the persistent communication request is marked as inactive.  Other nonblocking operations are deallocated and the request handle is set to MPI_REQUEST_NULL."

Basically, mention the special case of persistent requests first, so as to avoid the negative (non-persistent requests).

-Fab

Rolf Rabenseifner wrote on Sun, 12 Feb 2012 at 05:46:17

> When I understand correctly, then we have two problems:
> 
> 1. MPI-2.2 has the "bug" that MPI-2.2
>    page 53 line 47 - page 54 line 3, and page 54 lines 40-45
>    do not mention the generalize requests although it was intended
>    that MPI_Wait or MPI_Test of a generalized request acts
>    as it would have been a isend or irecv request.
> 2. Nobody has checked for nonblocking collectives and
>    nonblocking I/O that this text must now also include those routines.
> When I also understand correctly, then we currently say
> 
>   "If the communication object associated with this request
>    was created by a nonblocking send or receive all,
>    then ..."
> but we wanted to say
> 
>   "If the communication object associated with this request
>    is not a persistent communication request (see Section 3.9 on page 69),
>    then ..."
> Yes?
> 
> This change would solve both problems. Yes?
> 
> Best regards
> Rolf
> 
> 
> ----- Original Message -----
>> From: "Bronis R. de Supinski" <bronis at llnl.gov> To: "Fab Tillier"
>> <ftillier at microsoft.com> Cc: "Main MPI Forum mailing list"
>> <mpi-forum at lists.mpi-forum.org> Sent: Saturday, February 11, 2012
>> 7:57:30 PM Subject: Re: [Mpi-forum] MPI_WAIT/MPI_TEST and generalized,
>> I/O, and NBC requests I will leave it to you to decide. I am sure I
>> will be very pressed for time...
>> 
>> On Sat, 11 Feb 2012, Fab Tillier wrote:
>> 
>>> I think it would make more sense to fix the text for the WAIT and
>>> TEST routines, rather than spread the information around. The
>>> generalized request section might not need changes if we do this.
>>> 
>>> I don't know if I'll have time to put the text together before the
>>> meeting, though.
>>> 
>>> -Fab
>>> 
>>> Bronis R. de Supinski wrote on Sat, 11 Feb 2012 at 10:13:48
>>> 
>>>> 
>>>> I am fine with the decision to make it the chapter committee
>>>> responsibility. I suppose that means I need to draft text
>>>> for the generalized requests?
>>>> 
>>>> On Sat, 11 Feb 2012, William Gropp wrote:
>>>> 
>>>>> It looks like this is a result of adding new request types without
>>>>> revisiting
>>>>> the original text. Under generalized requests, there is text that
>>>>> seems to
>>>>> imply that the request is set to MPI_REQUEST_NULL on completion,
>>>>> but it
>>>>> isn't explicit and should be.
>>>>> 
>>>>> This is a chapter committee correction.
>>>>> 
>>>>> Bill
>>>>> 
>>>>> On Feb 10, 2012, at 6:04 PM, Fab Tillier wrote:
>>>>> 
>>>>> Hi Folks,
>>>>> 
>>>>> Looking at the text for MPI_WAIT (page 54, line 15) and MPI_TEST
>>>>> (page 55,
>>>>> line 7), it seems to imply that the request handle is only set to
>>>>> MPI_REQUEST_NULL for non-blocking send and receive requests. Are
>>>>> generalized, I/O, and NBC requests not completed the same way? Are
>>>>> users
>>>>> required to free such requests explicitly after they complete
>>>>> using
>>>>> MPI_REQUEST_FREE?
>>>>> 
>>>>> I would have expected that all request handles except those to
>>>>> persistent
>>>>> requests are set to MPI_REQUEST_NULL, and persistent request just
>>>>> rather
>>>>> marked inactive. If that is indeed the intent, shouldn't we update
>>>>> the text to
>>>>> reflect this? Is this a ticket-0 level change?
>>>>> 
>>>>> Thanks,
>>>>> -Fab
>>>>> 
>>>>> 
>>>>> _______________________________________________ mpi-forum mailing
>>>>> list mpi-forum at lists.mpi-forum.org<mailto:mpi-forum at lists.mpi-
>>>>> forum.org> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum
>>>>> 
>>>>> William Gropp
>>>>> Director, Parallel Computing Institute
>>>>> Deputy Director for Research
>>>>> Institute for Advanced Computing Applications and Technologies
>>>>> Paul and Cynthia Saylor Professor of Computer Science
>>>>> University of Illinois Urbana-Champaign
>>>>> 
>>>>> 
>>>>> 
>>>>> 
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