[petsc-users] Configuring petsc with MPI on ubuntu quad-core

[Vijay S. Mahadevan]

Hi,

I am trying to configure my petsc install with an MPI installation to
make use of a dual quad-core desktop system running Ubuntu. But
eventhough the configure/make process went through without problems,
the scalability of the programs don't seem to reflect what I expected.
My configure options are

--download-f-blas-lapack=1 --with-mpi-dir=/usr/lib/ --download-mpich=1
--with-mpi-shared=0 --with-shared=0 --COPTFLAGS=-g
--download-parmetis=1 --download-superlu_dist=1 --download-hypre=1
--download-blacs=1 --download-scalapack=1 --with-clanguage=C++
--download-plapack=1 --download-mumps=1 --download-umfpack=yes
--with-debugging=1 --with-errorchecking=yes

Is there something else that needs to be done as part of the configure
process to enable a decent scaling ? I am only comparing programs with
mpiexec (-n 1) and (-n 2) but they seem to be taking approximately the
same time as noted from -log_summary. If it helps, I've been testing
with snes/examples/tutorials/ex20.c for all purposes with a custom
-grid parameter from command-line to control the number of unknowns.

If there is something you've witnessed before in this configuration or
if you need anything else to analyze the problem, do let me know.

Thanks,
Vijay