[Beowulf] SPEC MPI2007

Tom Elken elken at pathscale.com
Thu Apr 26 08:23:11 PDT 2007

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.


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
tom.elken at qlogic.com      QLogic Corporation
650.934.8056              System Interconnect Group

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