Is there a way for users to know total memory allocated by MPICH at a certain time?  I am asking that since I want to know the difference of this value before/after a user function. The function is quite complex and calls many other functions.

  The background is that a PETSc user claimed a PETSc routine increased RSS (resident set size) periodically when running with MPICH, but not with OpenMPI.  The application itself is valgrind clean and has no memory leaks.

  Thank you.