[mpiwg-p2p] Result of reading of Info Query #63

[Rolf Rabenseifner]

I did not follow the discussion, but I want to
remember (for the case that some are not aware of)
that MPI_File_get_info returns not what the user set.
It returns all used info, system-specific infos 
plus those set by the user that are not ignored.

This works fine with all the parallel file-systems and their 
system-specific (i.e., non-user supplied?) values.

And of course, the user can learn from that and change those
values with MPI_File_set_info.

The wording for MPI_Win_get_info and MPI_Comm_get_info is the same.
See MPI-3.1, Sect. 6.4.4, page 250, lines 9-13, Advice to users.
(Same on page 502, lines 1-5)
And other wording in Sect. 11.2.7, page 415-416, lines 47ff, Adv. to impl.

Rolf 

----- Original Message -----
> From: "Daniel Holmes" <dholmes at epcc.ed.ac.uk>
> To: "MPI WG Point To Point Communications working group" <mpiwg-p2p at lists.mpi-forum.org>
> Sent: Wednesday, March 1, 2017 11:58:28 PM
> Subject: [mpiwg-p2p] Result of reading of Info Query #63

> Exec summary
> 
> The MPI_XXX_GET_INFO text is acceptable to everyone as is.
> 
> The MPI_XXX_SET_INFO text is contentious for two reasons:
> 1) (lack of) ability for MPI to pick non-user supplied values. Pavan brought
> this up. Resolution: none. Suggestions: continue arguing against this or add
> additional MPI_XXX_SET_INFO_INEXACT (or similar), which allows randomness -
> lets user choose.
> 2) (lack of) transactional behaviour - all key/value updates should succeed or
> all should fail. Martin brought this up. Resolution: this is a new API, we’d
> love to see your proposal.
> 
> Cheers,
> Dan.
> --
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> Scotland, with registration number SC005336.
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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
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