Using partial-order methods in the formal validation of industrial concurrent programs

Formal validation is a powerful technique for automatically checking that a collection of communicating processes is free from concurrency-related errors. Although validation tools invariably find subtle errors that were missed during thorough simulation and testing, the brute-force search they perform can result in excessive memory usage and extremely long running times. Recently, a number of researchers have been investigating techniques known as partial-order methods that can significantly reduce the computational resources needed for formal validation by avoiding redundant exploration of execution scenarios. This paper investigates the behavior of partial-order methods in an industrial setting. We describe the design of a partial-order algorithm for a formal validation tool that has been used on several projects that are developing software for the Lucent Technologies 5ESS(R) telephone switching system. We demonstrate the effectiveness of the algorithm by presenting the results of experiments with actual industrial examples drawn from a variety of 5ESS application domains.