Noise Makers Need to Know Where to be Silent – Producing Schedules That Find Bugs

A noise maker is a tool that seeds a concurrent program with conditional synchronization primitives, such as yield(), for the purpose of increasing the likelihood that a bug manifest itself. We introduce a novel fault model that classifies locations as "good", "neutral", or "bad," based on the effect of a thread switch at the location. Using the model, we explore the terms under which an efficient search for real-life concurrent bugs can be conducted. We accordingly justify the use of probabilistic algorithms for this search and gain a deeper insight of the work done so far on noise- making. We validate our approach by experimenting with a set of programs taken from publicly available multi-threaded benchmarks. Our empirical evidence demonstrates that real-life behavior is similar to one derived from the model.