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

Mon Feb 13 07:20:58 CST 2012

> 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.

Non-blocking I/O requests did not exist in MPI-2.2. 
They may come with MPI-3.0.

Yes, your text is perfect.
Do you file the ticket?
Please use official MPI-2.2 page and line numbers,
as in nearly all other tickets.
I would say, it is enough when you copy the paragraphes
mentioned in may email into the ticket.

As Change-log, I would recommend:

Section 3.7 on page 48.[[BR]]
It is clarified that MPI_Wait and MPI_Test set the request handle to
MPI_REQUEST_NULL if a generalized request is completed.

Best regards
Rolf

----- Original Message -----
> From: "Fab Tillier" <ftillier at microsoft.com>
> To: "Main MPI Forum mailing list" <mpi-forum at lists.mpi-forum.org>
> Sent: Monday, February 13, 2012 12:45:13 AM
> Subject: Re: [Mpi-forum] MPI_WAIT/MPI_TEST and generalized, I/O, and NBC requests
>
> 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
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>> _______________________________________________
> >>>> mpi-forum mailing list
> >>>> mpi-forum at lists.mpi-forum.org
> >>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum
> >>>
> >>>
> >> _______________________________________________
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> >
> 
> 
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-- 
Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de
High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
Nobelstr. 19, D-70550 Stuttgart, Germany . (Office: Allmandring 30)