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.