Scheduling Analysis and Optimization for Safety-Critical Automotive Systems

When designing safety-critical automotive systems, verification of timing and performance are key, especially the verification of hard deadlines and other critical timing constraints. Test- or simulation-based approaches suffer from corner-case coverage problems and are becoming less reliable as systems grow in size and complexity. Time-triggered mechanisms (e.g. OSEKtime and FlexRay) were proposed as a way out by providing better timing prediction. However, for reasons of cost, flexibility and reactivity, future cars will mostly likely contain a mix of event-triggered (ET) and time-triggered (TT) components that are combined synchronously and/or asynchronously, thereby further complicating timing. Scheduling analysis has recently matured to allow reliable timing verification and systematic optimization for ET, TT, and mixed systems. In this paper, we demonstrate the application of scheduling analysis in a SIL-3 software development and a safety-critical FlexRay-based distributed control system for which we calculate the worst-case end-to-end timing.