Parallel debugging (MPI) - Part 1

Parallel debugging (MPI) - Part 1

Ahem, ahem, searching a needle in a hay stack is easy compared to parallel debugging in MPI, or as a matter parallel debugging. Having overstated the problem in our hands, there are few solutions or workarounds of how to get our hands in the dirty waters and have some fun.

There are two ways (as always) to get our work done, either use free tools or give an arm or leg to buy a fancy debugger.

1. Fancy debuggers,  Allinea DDT, TotalView, Intel (Windows), Intel (Linux) to name some.

2. Free debuggers, gdb / valgrind to some extent, Eclipse PTP, etc

(Let us know for any others out there)

Read complete article by the chaps at OpenMPI.

1. gdb

gdb can be used as follows;

mpirun -np <NP> xterm -e gdb ./program

This the launches xterm windows in which I can do

run <arg1> <arg2> ... <argN>

Should work the same with ddd (GUI for gdb)

2. valgrind (more at this link)

First of all, you have to make sure that Valgrind 3.2.0 or later is installed, and Open MPI is compiled with Memchecker enabled. Then simply run you application with Valgrind, e.g.:

mpirun -np 2 valgrind ./program

3. Eclipse PTP 

Official page, Download page for Eclipse Parallel, Release Notes, 

More coming soon on this, looks interesting as they claim to have a parallel debugger !

Other Useful Links :

Some advanced tools, STAT.

A comparison on Wikipedia can be found here.