An efficient parallel critical path algorithm

The problem of identifying one of the longest sensitizable paths in a circuit is called a critical path problem. Several critical path algorithms have been proposed in the last few years. However, due to the long computation time required to produce accurate results, these algorithms may not be able to generate any result for large designs with many long false paths unless the accuracy of the results is compromised. Parallel processing seems to be an appropriate way to speed up the required computation. In this paper, we study the parallel algorithms for critical path problem. We first present a sensitization criterion. Based on this sensitization criterion an algorithm called DT-algorithm, which is a variation of the D-algorithm with stable time range of signals also taken into consideration, is developed. The DT-algorithm is especially suitable and can be used to determine the sensitizability of a given path in a parallel processing environment. We also present an implementation of parallel DT-algorithm that can be executed on a shared memory multiprocessor. The experimental results show that a reasonable speed-up can be obtained