DEPICT: a topology-based debugger for MPI programs
Simon Huband(Department of Computer Science & Software Engineering, The University of Western Australia
), Chris McDonald
To appear at (HIPS'01), San Francisco, California, USA, April 23, 2001
Abstract
Most parallel programs use regular topologies to support their
computation. Since they define the relationship between processes,
process topologies present an excellent opportunity for debugging. The
primary benefit is that patterns of expected behaviour can be abstracted
and identified, and unexpected behaviour reported.
However, topology support is inadequate in many environments, including
the popular Message Passing Interface (MPI). Programmers typically
implement topology support themselves, increasing the possibility of
introducing errors. Moreover, debugger support that exploits topological
abstract information is lacking.
We have undertaken to develop a debugger that exploits topological
information. This paper presents DEPICT (DEbugger of Parallel but
Inconsistent Communication Traces), a (preliminary) topology-based
debugger for MPI. Currently, DEPICT presents high-level visualisations
of parallel program communication behaviour, where logically similar
processes are clearly indicated in a manner that allows the programmer
insight into overall program behaviour. To assist in understanding
unexpected behaviour, DEPICT allows programmers to investigate the
observed semantic differences between processes.
