I have a problem with openmpi1.3, ifort+mkl v11.1 in Ubuntu10.04 systems (32 or 64bit). My code worked in Ubuntu8.04 and works in RedHat based systems, with slightly different version changes on mkl and ifort. There were no changes in the source code.
The problem is that the application works for small cell sizes per core, but not for large cell sizes per core. And it always works for 1 core.
Example: a grid with 1.2Million cells does not work with mpiexec -n 4 <my_app> but it works with mpiexec -n 32 <my_app>. It seems that there is a maximum of cell/core. And it works with <my_app>.
Is this a stack size (or any memory problem)? Should I set the ulimit -s unlimited not only on my bashrc but also in the ssh environment (and how)? Or is something else?
Thanks for any help.