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

Mon Feb 13 10:32:07 CST 2012

Rajeev and Fab,

yes, you are both right.
Then we need a change-log like

> > 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 also a generalized or I/O request is completed.

----- Original Message -----
> From: "Rajeev Thakur" <thakur at mcs.anl.gov>
> To: "Main MPI Forum mailing list" <mpi-forum at lists.mpi-forum.org>
> Sent: Monday, February 13, 2012 3:32:47 PM
> Subject: Re: [Mpi-forum] MPI_WAIT/MPI_TEST and generalized, I/O, and NBC requests
> Nonblocking *independent* I/O requests existed in MPI-2. Nonblocking
> collective I/O may come in MPI-3.
> 
> Rajeev
> 
> On Feb 13, 2012, at 7:20 AM, Rolf Rabenseifner wrote:
> 
> >> 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
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>> _______________________________________________
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> >>>>>
> >>>>>
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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)
> > _______________________________________________
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> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum
> 
> 
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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)