Modeling concurrency in parallel debugging

Abstract

We propose a debugging language, Data Path Expressions (DPEs), for modeling the behavior of parallel programs. The debugging paradigm is for the programmer to describe the expected program behavior and for the debugger to compare the actual program behavior during execution to detect program errors. We classify DPEs into five subclasses according to syntactic criteria, and characterize their semantics in terms of a hierarchy of extended Petri Net models. The characterization demonstrates the power of DPEs for modeling parallelism. We present predecessor automata as a mechanism for implementing the third subclass of DPEs, which expresses bounded parallelism. Predecessor automata extend finite state automata to provide efficient event recognizers for parallel debugging. We briefly describe the application of DPEs to race conditions, deadlock and starvation.