passert: A Tool for Debugging Parallel Programs

passert is a new debugging tool for parallel programs which allows programmers to express correctness criteria using a simple, expressive assertion language. We demonstrate how these parallel assertions allow the detection and diagnosis of real world concurrency bugs, detecting 14/17 bugs in an independently selected set of bugs from open source software. We describe a runtime checker which allows automatic checking of parallel assertions in C and C++ programs, with a geometric mean of 6.6× overhead on a set of PARSEC benchmarks. We improve performance by introducing a relaxed timing semantics for parallel assertions, which better reflects real memory models, and exposes more bugs with less overhead (geometric mean overhead 3.5×).