[Mpi-comments] "safe" tag in MPI_Intercomm_create

[William Gropp]

Good point.  This moves this to MPI-next.

Bill

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



On Sep 7, 2012, at 12:22 PM, Rolf Rabenseifner wrote:

> If we ever make this routine a nonblocking collective,
> the tag may be needed again, because I expect that
> then, no two nonblocking MPI_Intercomm_create can be 
> active with the same tag.
> 
> This means, one may include backward and future use.
> It should not be a dummy. It should continue to
> require to have a valid tag, i.e., in the tag space 
> between 0 and the value returned with inquiring MPI_TAG.
> 
> Rolf
> 
> ----- Original Message -----
>> From: "William Gropp" <wgropp at illinois.edu>
>> To: "Comments on the MPI Standard" <mpi-comments at lists.mpi-forum.org>
>> Sent: Friday, September 7, 2012 5:55:14 PM
>> Subject: Re: [Mpi-comments] "safe" tag in MPI_Intercomm_create
>> Is this an MPI-next or a ticket zero change? Is this a chapter
>> committee change (I think it should be, but I don't want to make that
>> call unilaterally)?
>> 
>> Bill
>> 
>> 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
>> 
>> 
>> 
>> On Sep 6, 2012, at 5:36 PM, Jim Dinan wrote:
>> 
>>> Hi Bill,
>>> 
>>> That's right, the tag argument is vestigial as of MPI 3.0. I agree
>>> with your suggestion of changing '"safe" tag' to:
>>> 
>>> dummy - Ignored argument, retained for backward compatibility.
>>> 
>>> ~Jim.
>>> 
>>> On 9/6/12 5:02 PM, William Gropp wrote:
>>>> I noted in ticket #305 that the argument is now ignored and
>>>> retained only for backward compatibility. Deleting "safe" isn't
>>>> enough.
>>>> 
>>>> Bill
>>>> 
>>>> 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
>>>> 
>>>> 
>>>> 
>>>> On Sep 6, 2012, at 1:47 PM, Jim Dinan wrote:
>>>> 
>>>>> Hi All,
>>>>> 
>>>>> It looks like we forgot to include the removal of the "safe"
>>>>> qualifier from the tag argument as a part of the change to
>>>>> MPI_Intercomm_create:
>>>>> 
>>>>> https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/305
>>>>> 
>>>>> Specifying that the tag argument must be "safe" was made
>>>>> unnecessary by this change, since it eliminates the possibility of
>>>>> interference with user communication.
>>>>> 
>>>>> ~Jim.
>>>>> _______________________________________________
>>>>> mpi-comments mailing list
>>>>> mpi-comments at lists.mpi-forum.org
>>>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-comments
>>>> 
>>>> 
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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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