A Parallelism Analyzer for Conservative Parallel Simulation

Most small-scale simulation applications are implemented by sequential simulation techniques. As the problem size increases, however, sequential techniques may be unable to manage the time complexity of the simulation applications adequately. It is natural to consider re-implementing the corresponding largescale simulations using parallel techniques, which have been reported to be successful in reducing the time complexity for several examples. However, parallel simulation may not be effective for every application. Since the implementation of parallel simulation for an application is usually very expensive, it is required to investigate the performance of parallel simulation for a particular application before re-implementing the simulation. The Chandy-Misra parallel, discrete-event simulation paradigm has been utilized in many large-scale simulation experiments, and several significant extensions have been based on it. Hence the Chandy-Misra protocol is adopted here as a basic model of parallel simulation to which our performance prediction techniques are applied. For an existing sequential simulation program based on the process interaction model, this paper proposes a technique for evaluating Chandy-Misra parallel simulation without actually implementing the parallel program. The idea is to insert parallelism analysis code into the sequential simulation program. When the modified sequential program is executed, the time complexity of the parallel simulation based on the ChandyMisra protocol is computed. Our technique has been used to determine whether a giant Signaling System 7 simulation (sequential implementation) should be re-implemented using the parallel simulation approach.