Hi there, I'm using PETSc MATMPIAIJ and ksp solver. It seems that PETSc will run obviously faster if I set the number of CPUs close to the number of computer nodes in the job file. By default MPIAIJ matrix is stored in different processors and ksp solver will communicate for each step, however since on each node several CPUs share the same memory while ksp may still try to communicate through network card, this may mess up a bit. Is there any way to detect which CPUs are sharing the same memory? Thanks a lot.
Best, Xiaoyin Ji
