Maximizing synchronization coverage via controlling thread schedule

Coverage analysis has been playing an important role in testing traditional single threaded applications. As the number of multicore hardware being used increases, the number of multithreaded applications grows as well. In multi-threaded environment, traditional code coverage models cannot really cover the nondeterministic behavior of simultaneously running threads. The concept of synchronization coverage was invented to solve this problem. In this paper, we present a new coverage testing tool which maximizes synchronization coverage rates with less time and repetition. After searching for synchronization primitives, our tool instruments special code segments to these points and forces the application executions to maximize its synchronization coverage by scheduling individual threads. This enables achieving maximum synchronization coverage without manipulating source code or writing unit test code. We implemented this method and showed that our method achieves maximum synchronization coverage rates 1.5 to over 144 times faster than random method.