PGDB: A Debugger for MPI Applications

Nikoli Dryden

Abstract: As MPI applications scale to larger machines, errors that had been hidden from testing at smaller scales begin to manifest themselves. It is therefore necessary to extend debuggers to work at these scales, in order for efficient development of correct applications to proceed. PGDB is the Parallel GDB, an open-source debugger for MPI applications that provides such a capability. It is designed from the ground up to be a robust debugging environment at scale, while presenting an interface similar to that of the typical command-line GDB debugger. Its usage on representative debugging problems is demonstrated and its scalability on the Stampede supercomputer is evaluated.