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<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2>Thanks. Good idea. A first take on the
subsetting follows:</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2>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?</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2>Very valuable</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2>Probably valuable</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2>Probably useless</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2>Useless</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=744315122-17112009><FONT face=Arial
color=#0000ff size=2>Harmful</FONT></SPAN></DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> mpi-forum-bounces@lists.mpi-forum.org
[mailto:mpi-forum-bounces@lists.mpi-forum.org] <B>On Behalf Of </B>Richard
Treumann<BR><B>Sent:</B> Tuesday, November 17, 2009 6:48 PM<BR><B>To:</B> Main
MPI Forum mailing list<BR><B>Subject:</B> Re: [Mpi-forum] MPI user
survey<BR></FONT><BR></DIV>
<DIV></DIV>
<P>I will leave it to Alexander to for a question about subsetting if he wishes
to. Here is one about assertions.<BR><BR>The MPI standard provides certain
semantic guarantees that may not be required by a <BR>particular application. It
also provides functions that many applications never use. If MPI-3<BR>provided
an "assertions" interface that would let an application identify
specific<BR>functionality it does not depend on and an MPI library could improve
performance or reduce <BR>memory usage by disabling that specific functionality,
how valuable might that interface be?<BR><BR>Very valuable<BR>Probably
valuable<BR>Probably useless<BR>useless<BR>harmful<BR><BR><BR>Dick Treumann -
MPI Team <BR>IBM Systems & Technology Group<BR>Dept X2ZA / MS P963 -- 2455
South Road -- Poughkeepsie, NY 12601<BR>Tele (845) 433-7846 Fax (845)
433-8363<BR><BR><BR><TT>mpi-forum-bounces@lists.mpi-forum.org wrote on
11/17/2009 11:40:03 AM:<BR><BR>> [image removed] </TT><BR><TT>> <BR>>
Re: [Mpi-forum] MPI user survey</TT><BR><TT>> <BR>> Jeff Squyres
</TT><BR><TT>> <BR>> to:</TT><BR><TT>> <BR>> Main MPI Forum mailing
list</TT><BR><TT>> <BR>> 11/17/2009 11:41 AM</TT><BR><TT>> <BR>>
Sent by:</TT><BR><TT>> <BR>>
mpi-forum-bounces@lists.mpi-forum.org</TT><BR><TT>> <BR>> Please respond
to Main MPI Forum mailing list</TT><BR><TT>> <BR>> On Nov 17, 2009, at
8:16 AM, Supalov, Alexander wrote:<BR>> <BR>> > No objections - let's
go for 2 separate questions, e.g.:<BR>> ><BR>> > "Do you want to
achieve higher performance by disabling certain <BR>> > MPI-3
features in your program?<BR>> <BR>> I do not think that this is a
well-formed question.<BR>> <BR>> It directly states something that has not
been well defined (or even <BR>> accepted) by the Forum.
Specifically: it is *by no means guaranteed* <BR>> that you will
get higher performance by disabling certain MPI-3 <BR>> features.
Heck, we don't even know precisely what MPI-3 features will <BR>>
exist!<BR>> <BR>> > "If so, do you prefer subsetting or
assertions?"<BR>> <BR>> The others questions contain at least a hint of
context so that <BR>> respondents have a clue as to how to answer.
This one explains <BR>> neither "subsetting" nor "assertions".
I suspect that 95% of <BR>> respondents will not know how to
answer.<BR>> <BR>> -- <BR>> Jeff Squyres<BR>>
jsquyres@cisco.com<BR>> <BR>>
_______________________________________________<BR>> mpi-forum mailing
list<BR>> mpi-forum@lists.mpi-forum.org<BR>> <A
href="http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum">http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum</A><BR></TT></P><pre>---------------------------------------------------------------------
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