[Mpi-forum] MPI user survey
alexander.supalov at intel.com
Tue Nov 17 16:57:57 CST 2009
Thanks. Good idea. A first take on the subsetting follows:
The MPI-3 standard is going to provide several substantial extensions to the existing MPI standard. Some of them may or may not be needed for all MPI-3 applications. At the same time, runtime support for the complete set of the MPI-3 features may incur additional implementation complexity and hence probably performance and/or memory space penalty on the rest of the MPI implementation (think dynamic processes in the case of MPI-2, for one). Subsetting, i.e., a facility intended to determine a working subset of the MPI features needed for a particular application, was proposed as one way of managing the increasing complexity of the MPI standard on a per application basis. If such a facility were included into the MPI-3 standard, how useful might that be to you?
From: mpi-forum-bounces at lists.mpi-forum.org [mailto:mpi-forum-bounces at lists.mpi-forum.org] On Behalf Of Richard Treumann
Sent: Tuesday, November 17, 2009 6:48 PM
To: Main MPI Forum mailing list
Subject: Re: [Mpi-forum] MPI user survey
I will leave it to Alexander to for a question about subsetting if he wishes to. Here is one about assertions.
The MPI standard provides certain semantic guarantees that may not be required by a
particular application. It also provides functions that many applications never use. If MPI-3
provided an "assertions" interface that would let an application identify specific
functionality it does not depend on and an MPI library could improve performance or reduce
memory usage by disabling that specific functionality, how valuable might that interface be?
Dick Treumann - MPI Team
IBM Systems & Technology Group
Dept X2ZA / MS P963 -- 2455 South Road -- Poughkeepsie, NY 12601
Tele (845) 433-7846 Fax (845) 433-8363
mpi-forum-bounces at lists.mpi-forum.org wrote on 11/17/2009 11:40:03 AM:
> [image removed]
> Re: [Mpi-forum] MPI user survey
> Jeff Squyres
> Main MPI Forum mailing list
> 11/17/2009 11:41 AM
> Sent by:
> mpi-forum-bounces at lists.mpi-forum.org
> Please respond to Main MPI Forum mailing list
> On Nov 17, 2009, at 8:16 AM, Supalov, Alexander wrote:
> > No objections - let's go for 2 separate questions, e.g.:
> > "Do you want to achieve higher performance by disabling certain
> > MPI-3 features in your program?
> I do not think that this is a well-formed question.
> It directly states something that has not been well defined (or even
> accepted) by the Forum. Specifically: it is *by no means guaranteed*
> that you will get higher performance by disabling certain MPI-3
> features. Heck, we don't even know precisely what MPI-3 features will
> > "If so, do you prefer subsetting or assertions?"
> The others questions contain at least a hint of context so that
> respondents have a clue as to how to answer. This one explains
> neither "subsetting" nor "assertions". I suspect that 95% of
> respondents will not know how to answer.
> Jeff Squyres
> jsquyres at cisco.com
> mpi-forum mailing list
> mpi-forum at lists.mpi-forum.org
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