Performance Analysis of Time Warp Simulation with Cascading Rollbacks

This paper presents an analytical model for evaluating the performance of Time Warp simulators. The pro-posed model is formalized based on two important time components in parallel and distributed processing: com-putatzon time and communication time. The communi-cotton time is modeled by buffer access time and mes-sage transmission time. Logical processes of the Time Warp simulation, and the processors executing them are assumed to be homogeneous. Performance metrics such as rollback probability, rollback distance, elapsed time and Time Warp efficiency are derltied. More impor-tantly, rre also analyze the zmpact of cascading rollback waves on the overall Time Warp performance. By ren-dering the deviation in state numbers of sender-receiver pairs, we investigate the performance of throttled Time Warp scheme. Our analytical model shows that the de-viation in state numbers and the communication delay have a profound impact on Time Warp efficiency. The performance model has been validated against imple-mentation results obtained on a Fujitsu =1 P3000 parallel computer. The analytical framework can be readily used to estimate performance before the Time Warp simula-tor is rmplemented.