Verifying Parallel Programs with MPI-Spin

Standard testing and debugging techniques are notoriously ineffective when applied to parallel programs, due to the numerous sources of nondeterminism arising from parallelism. MPI-Spin, an extension of the model checker Spin for verifying and debugging MPI-based parallel programs, overcomes many of the limitations associated with the standard techniques. By exploring all possible executions of an MPI program, MPI-Spin can conclude, for example, that a program cannot deadlock on any execution. If the program can deadlock, MPI-Spin can exhibit a trace showing exactly how the program fails, greatly facilitating debugging. This tutorial will serve as an introduction to MPI-Spin. Through a series of examples and exercises, participants will learn to use MPI-Spin to check for deadlocks, race conditions, and discrepancies in the numerical computations performed by MPI programs. The only prerequisites are familiarity with C and the basic MPI operations; no prior verification experience is required. Participants are encouraged to download and install MPI-Spin before the tutorial, following the instructions at http://vsl.cis.udel.edu/mpi-spin. The tutorial is divided into four parts, each lasting approximately 45 minutes: (1) introduction and tool demonstration, (2) language basics, (3) using MPISpin, and (4) verifying correctness of numerical computations.