[Mpi-forum] MPI_WAIT/MPI_TEST and generalized, I/O, and NBC requests
Fab Tillier
ftillier at microsoft.com
Mon Feb 13 11:42:50 CST 2012
So are we back to needing a ticket for this then? Or is it still at the discretion of the chapter authors?
-Fab
Rolf Rabenseifner wrote on Mon, 13 Feb 2012 at 08:32:07
> 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
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>>>>>>>>>
>>>>>>>>> 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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>>> --
>>> 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 . . .
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