Scheduling complex automotive embedded real-time systems

Abstract

The formal verification of task schedulability is getting more important in the automotive domain as more and more applications are integrated into domain specific controllers. Especially for safety critical applications an indepth knowledge about the worst-case response time of tasks is of utmost importance. Such systems often consist of subsystems that comprise of a collection of tasks, called transactions, which are triggered by external events. We adapt a well known response time analysis to analyze asynchronous task sets where subsets may be triggered from different clock references. Therefore we refine the original computational model from the literature to capture the information about transaction clock references. To determine the schedulability of the system we first analyze all task subsets which are triggered by the same clock reference. Then we combine the results to derive the response times for the complete task set. The approach incorporates no overestimation of the response times and therefore represets a necessary and sufficient schedulability test for such systems. The computational complexity of the presented approach is O(nm) with n being the number of tasks and m the number of clock references in the system. We apply the analysis to a real-world scenario from the automotive safety domain to confirm the computational