[mvapich-discuss] Possible mvapich bug (possibly not as well).

[Dhabaleswar Panda]

Thanks for your report. What is your computing platform and how much
memory your computing nodes have (per processor/core)? Does your
application (using the 38381x38381 PDSYGST configuration) require more
memory than being available on these platforms. As you might be knowing,
if you run an application which requires higher amount of memory than
being available, a lot of swapping will occur and your computation will
not be able to make progress. Not sure whether this is the situation you
are encountering. Does this problem happen for this exact matrix size? Are
you able to run your application with any higher sized matrix?

If it is a multi-core-based cluster, can you run your application using
more nodes and less cores/node while keeping the total number of cores for
the application constant (such as using 8 nodes with 4 cores/node vs.  4
nodes with 8 cores/node). If the application runs with the first
configuration but not with the second configuration, it will show that you
are getting constrained by the amount of memory being available per
core/node.


Thanks,

DK

On Fri, 19 Sep 2008, Laurence Marks wrote:

> I have a highly reproducible, but so far untraceable problem. It could
> be due to mvapich, but also not.
>
> In a code which calls the scalapack subroutine PDSYGST (which uses two
> distributed matrices), if the matrices are 36927x36927 it works fine;
> if they are 38381x38381 it runs forever, i.e.until I kill it.
>
> This behavior occurs for the Intel mkl versions 10.0.3.020,
> 10.0.4.023, 10.1.0.009 and ifort/icc versions 10.1.015 and 10.1.018.
> It occurs for both an April 2008 svn of mvapich, and an svn of a few
> days ago. It also occurs with OFED-1.2.5.5 and OFED-1.3.
>
> I would welcome any suggestions.
>
> --
> Laurence Marks
> Department of Materials Science and Engineering
> MSE Rm 2036 Cook Hall
> 2220 N Campus Drive
> Northwestern University
> Evanston, IL 60208, USA
> Tel: (847) 491-3996 Fax: (847) 491-7820
> email: L-marks at northwestern dot edu
> Web: www.numis.northwestern.edu
> Chair, Commission on Electron Crystallography of IUCR
> www.numis.northwestern.edu/IUCR_CED
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