Program Visualization for Debugging Deadlocks in Multithreaded Programs

Abstract

Debugging deadlocks in multithreaded programs is a notoriously difficult task. A key reason for this is to understand the high behavioral complexity resulting from the inherent nondeterminism of multithreaded programs. We present a novel visualization technique which abstracts the nested patterns of locks and represents the happens-before relation of the patterns. We implement the technique in a prototype tool for Java, and demonstrate its power using a number of multithreaded Java programs. The experimental result shows that this graph provides a simple yet powerful representation to reason about deadlocks in an execution instance.