Tom,
As to the importance of a2a and variants, from the top of my mind:
* STAR-CD (version 3) from CD-ADAPCO uses solely MPI_Alltoallv
* IS (integer sort) from NAS kernels uses MPI_Alltoallv
* LS-DYNA from Livermore Software, aprox. 25%
of the time in the MPI library is consumed in
MPI_Alltoall (32p, neon_refined_revised dataset)
* Matrix transpose often uses MPI_Alltoall
so, yes, I am pretty convinced this is a hole which should be filled.
Håkon
At 17:23 26.04.2007, Tom Elken wrote:
Hi Håkon,
Since that presentation was written, the 18
benchmarks were pruned down to 13 for various
reasons, but none added, so there are still no
applications with MPI_Alltoall or MPI_Alltoallv
in the suite. We didn't know about this lack until you pointed it out.
It is unclear how important is this lack. It
could be that applications writers try to avoid
these calls when trying to write scalable
applications. Also the fact that 18
applications picked more or less at random
(while trying to find scalable, publicly
available applications from a wide range of
disciplines) did not use these calls, may mean
something. There is one benchmark still in the
suite whose source contains MPI_Alltoall calls,
but the test cases we run do not use that function.
But still, the HPG committee will entertain
adding such benchmarks for later versions of the benchmark suite.
Thanks,
Tom
Håkon Bugge wrote:
From the reference below, 18 benchmarks are
characterized; viewgraph 15 and 16 show the
"Message call count". Of the 18 benchmarks,
none use MPI_Alltoall or MPI_Alltoallv. Now,
if the suite has been amended with benchmarks
using MPI_Alltoall, we're only lacking benchmarks using MPI_Alltoallv.
And to be precise, I do not search for said
benchmarks personally; my intent was to
underline that this dimension was missing from
the 18 (initial) benchmarks in the MPI2007 suite.
Thanks, Håkon
you wrote:
----------------
I just read
http://www.spec.org/workshops/2007/austin/slides/SPEC_MPI2007.pdf
--
~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tom Elken Manager, Performance Engineering
[EMAIL PROTECTED] QLogic Corporation
650.934.8056 System Interconnect Group
--
Håkon Bugge
CTO
dir. +47 22 62 89 72
mob. +47 92 48 45 14
fax. +47 22 62 89 51
[EMAIL PROTECTED]
Skype: hakon_bugge
Scali - http://www.scali.com
Scaling the Linux Datacenter
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