Sounds good to me. The tag is still usefull as a security argument: If one process provides another tag (i.e., a wrong tag), then this routine may or will produce a deadlock, similar to pt-to-pt. Rolf ----- Original Message -----

From: "Jim Dinan" <[email protected]> To: [email protected] Sent: Friday, September 7, 2012 8:14:29 PM Subject: Re: [Mpi-comments] "safe" tag in MPI_Intercomm_create I think that we should delete "safe" and leave any further changes for MPI-next.

~Jim.

On 9/7/12 12:44 PM, William Gropp wrote:

...

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" <[email protected]> To: "Comments on the MPI Standard" <[email protected]> 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 [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-comments

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-- Dr. Rolf Rabenseifner . . . . . . . . . .. email [email protected] 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) _______________________________________________ mpi-comments mailing list [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-comments

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-- Dr. Rolf Rabenseifner . . . . . . . . . .. email [email protected] 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)