Using MPICH P4 procgroup Files

Debugging Memory Problems with MemoryScape™ : Chapter 4 Creating Programs for Memory Debugging : Setting Up MPI Debugging Sessions : Debugging MPICH Applications : Using MPICH P4 procgroup Files

If you’re using MPICH with a P4 procgroup file (by using the -p4pg option), you must use the same absolute path name in your procgroup file and on the mpirun command line. For example, if your procgroup file contains a different path name than that used in the mpirun command, even though this name resolves to the same executable, MemoryScape assumes that it is a different executable, which causes debugging problems.

The following example uses the same absolute path name on the MemoryScape command line and in the procgroup file:

% cat p4group
local 1 /users/smith/mympichexe
bigiron 2 /users/smith/mympichexe
% mpirun -p4pg p4group -tv /users/smith/mympichexe

In this example, MemoryScape does the following:

1 Reads the symbols from mympichexe only once.

2 Places MPICH processes in the same MemoryScape share group.

3 Names the processes mypichexe.0, mympichexe.1, mympichexe.2, and mympichexe.3.

If MemoryScape assigns names such as mympichexe<mympichexe>.0, a problem occurred and you need to compare the contents of your procgroup file and mpirun command line.