Formal verification of scalable nonzero indicators
Shao Jie Zhang, Yang Liu, Jun Sun, Jin Song Dong, Wei Chen, Yanhong A. Liu · 2009
Concurrent algorithms are notoriously difficult to design correctly, and high performance algorithms that make little or no use of locks even more so. In this paper, we describe a formal verification of a recent concurrent data structure Scalable NonZero Indicators. The algorithm supports incrementing, decrementing, and querying the shared counter in an efficient and linearizable way without blocking. The algorithm is highly non-trivial and it is challenging to prove the correctness. We have proved that the algorithm satisfies linearizability, by showing a trace refinement relation from the concrete implementation to its abstract specification. These models are specified in CSP and verified automatically using the model checking toolkit PAT. 1