Compositional Sequentialization of Periodic Programs

Sagar Chaki, Arie Gurfinkel, Soonho Kong, Ofer Strichman, Proceedings of the 14th International Conference on Verification, Model Checking and Abstract Interpretation (VMCAI), page 536--554, January 20--23, 2013.

Abstract: We advance the state-of-the-art in verifying periodic programs -- a commonly used form of real-time software that consists of a set of asynchronous tasks running periodically and being scheduled preemptively based on their priorities. We focus on an approach based on sequentialization -- reducing the verification of a time-bounded periodic program to that of an equivalent sequential program. We present a new compositional form of sequentialization that improves on earlier work in terms of both scalability and completeness (i.e., false warnings) by leveraging temporal separation between jobs in the same hyper-period and across multiple hyper-periods. We also show how the new sequentialization can be further improved in the case of harmonic systems to generate sequential programs of asymptotically smaller size. Experiments indicate that our new sequentialization improves verification time by orders of magnitude compared to competing schemes.

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