A Simulation Methodology for Worst-Case Response Time Estimation of Distributed Real-Time Systems

In this paper, we propose a simulation-based methodology for worst-case response time estimation of distributed real-time systems. Schedulability analysis produces pessimistic upper bounds on process response times. Consequently, such an analysis can lead to overdesigned systems resulting in unnecessarily increased costs. Simulations, if well conducted, can lead to tight lower bounds on worst-case response times, which can be an essential input at design time. Moreover, such a simulation methodology is very important in situations when the running application or the underlying platform is such that no formal timing analysis is available. Another important application of the proposed simulation environment is the validation of formal analysis approaches, by estimating their degree of pessimism. We have performed such an estimation of pessimism for two response-time analysis approaches for distributed embedded systems based on two of the most important automotive communication protocols: CAN and FlexRay.