The Impact of Concurrent Coverage Metrics on Testing Effectiveness

When testing multithreaded programs, the number of possible thread interactions makes exploring all interactions infeasible in practice. In response, researchers have developed concurrent coverage metrics for multithreaded programs. These metrics allow them to estimate how well they have exercised concurrent program behavior, just as branch and statement coverage metrics do for sequential program testing. However, unlike sequential coverage metrics, the effectiveness of concurrent coverage metrics in testing remains largely unexamined. In this paper, we explore the relationship between concurrent coverage and fault detection effectiveness by studying the application of eight concurrent coverage metrics in testing nine concurrent programs. Our results show that existing concurrent coverage metrics are often moderate to strong predictors of concurrent testing effectiveness, and are generally reasonable targets for test suite generation. Nevertheless, their relative effectiveness as predictors and test generation targets varies across programs, and thus additional work is needed in this area.