Atomizer: A dynamic atomicity checker for multithreaded programs

Ensuring the correctness of multithreaded programs is difficult, due to the potential for unexpected interactions between concurrent threads. Much previous work has focused on detecting race conditions, but the absence of race conditions does not by itself prevent undesired interactions between threads.A more fundamental noninterference property is atomicity. A method is atomic if its execution is not affected by and does not interfere with concurrently-executing threads. Atomic methods can be understood according to their sequential semantics, which significantly simplifies both formal and informal correctness arguments.This paper presents a dynamic analysis for detecting atomicity violations. This analysis combines ideas from both Lipton’s theory of reduction and earlier dynamic race detectors. Experience with a prototype checker for multithreaded Java code demonstrates that this approach is effective for detecting errors due to unintended interactions between threads. In particular, our atomicity checker detects errors that would be missed by standard race detectors. Our experimental results also indicate that the majority of methods in our benchmarks are atomic, indicating that atomicity is a standard methodology in multithreaded programming.