[Mpi-forum] Final Reminder: Deadline for Ballots, Readings, ... for the August MPI Forum Meeting is Tomorrow/Monday

[Rolf Rabenseifner]

Dear all,

I updated the issue based on the discussion today:

https://github.com/mpi-forum/mpi-issues/files/5086553/mpi-report-issue120-topol-2020-08-17-annotated-pages334-335.pdf

contains the change for the no-no-vote tomorrow.

Best regards and thanks to all for this thorough review,
Rolf


----- Original Message -----
> From: "Main MPI Forum mailing list" <mpi-forum at lists.mpi-forum.org>
> To: "Main MPI Forum mailing list" <mpi-forum at lists.mpi-forum.org>
> Cc: "Guillaume Mercier" <guillaume.mercier at u-bordeaux.fr>
> Sent: Monday, August 3, 2020 6:39:24 PM
> Subject: Re: [Mpi-forum] Final Reminder: Deadline for Ballots, Readings, ... for the August MPI Forum Meeting is
> Tomorrow/Monday

> Hi all,
> 
> The Hardware Topologies Working Group wants to announce the first vote
> for the MPI_Cart_create_weighted / Topology aware Cartesian communicators:
> 
> Annotated pdf as read in the June 2020 meeting:
> https://github.com/mpi-forum/mpi-issues/files/4823780/mpi-report-issue120-topol-2020-06-14-annotated.pdf
> 
> Issue https://github.com/mpi-forum/mpi-issues/issues/120
> PR#98 https://github.com/mpi-forum/mpi-standard/pull/98
> 
> This is one of the tickets for MPI-4.0 for performance enhancements.
> 
> It fills the gap that the MPI-1.1 MPI_Dims_create wasn't hardware nor
> application topology aware.
> 
> For this, it combines both functionalities,
> - the factorization of #processes into the given number of dimensions
>    (as non-hardware/application aware in MPI_Dims_create)
> - the reordering of the processes and providing comm_cart
>    (as in MPI_Cart_create)
> into one new hardware & application aware routine: MPI_Cart_create_weighted.
> 
> The hardware awareness comes through the old_comm,
> the application awareness through the weights.
> 
> 
> The design of the interface was developed with the help of many forum
> members (thanks a lot!) and is along the principles we already use for
> the weights for graph topologies for application topology awareness.
> This also means, there is enough room for further research and
> development through an info argument to allow additional features in the
> future or for specific vendor platforms.
> 
> The interface is as simple as possible according to the main goal of
> MPI as defined on page 1 of all MPI standards:
> 
> "The goal of the Message-Passing Interface simply stated is to
> develop a widely used standard for writing message-passing programs.
> As such the interface should establish a practical, portable,
> efficient, and flexible standard for message passing."
> 
> For Cartesian applications, the new interface fulfills this short list
> of being "practical, portable, efficient, and flexible" and can be
> widely used for all applications that use already the old MPI-1.1
> interface MPI_Dims_create + MPI_Cart_create to realize better
> hardware-awareness and to allow also application-awareness through
> the new weights.
> 
> And for portable development of MPI applications, it is equally
> important that the new interface is part of the MPI standard as it
> was for the old Cartesian interface. In addition, best optimization
> may require knowledge of the hardware which may not be disclosed
> to the public which would prevent third party solutions - this serves
> as second argument to vote the new interface into the MPI library.
> 
> Therefore, we'll be glad if you vote for this new performance
> oriented interface for MPI-4.0.
> 
> And thank you for reading this announcement to the end.
> 
> Best regards,
> Guillaume and the Hardware Topologies Working Group
> 
> 
> 
> 
> 
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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: Room 1.307) .