On Wed, Feb 2, 2011 at 4:46 PM, Vijay S. Mahadevan <span dir="ltr"><<a href="mailto:vijay.m@gmail.com">vijay.m@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi,<br>
<br>
I am trying to configure my petsc install with an MPI installation to<br>
make use of a dual quad-core desktop system running Ubuntu. But<br>
eventhough the configure/make process went through without problems,<br>
the scalability of the programs don't seem to reflect what I expected.<br>
My configure options are<br>
<br>
--download-f-blas-lapack=1 --with-mpi-dir=/usr/lib/ --download-mpich=1<br>
--with-mpi-shared=0 --with-shared=0 --COPTFLAGS=-g<br>
--download-parmetis=1 --download-superlu_dist=1 --download-hypre=1<br>
--download-blacs=1 --download-scalapack=1 --with-clanguage=C++<br>
--download-plapack=1 --download-mumps=1 --download-umfpack=yes<br>
--with-debugging=1 --with-errorchecking=yes<br></blockquote><div><br></div><div>1) For performance studies, make a build using --with-debugging=0</div><div><br></div><div>2) Look at -log_summary for a breakdown of performance</div>
<div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Is there something else that needs to be done as part of the configure<br>
process to enable a decent scaling ? I am only comparing programs with<br>
mpiexec (-n 1) and (-n 2) but they seem to be taking approximately the<br>
same time as noted from -log_summary. If it helps, I've been testing<br>
with snes/examples/tutorials/ex20.c for all purposes with a custom<br>
-grid parameter from command-line to control the number of unknowns.<br>
<br>
If there is something you've witnessed before in this configuration or<br>
if you need anything else to analyze the problem, do let me know.<br>
<br>
Thanks,<br>
<font color="#888888">Vijay<br>
</font></blockquote></div><br><br clear="all"><br>-- <br>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener<br>