Parametric Schedulability Analysis of Fixed Priority Real-Time Distributed Systems

In this paper, we address the problem of parametric schedu- lability analysis of distributed real-time systems scheduled by fixed priority. We propose two different approaches to parametric analysis. The first one is a novel analytic technique that extends single-processor sensitivity analysis to the case of distributed systems. The second approach is based on model checking of Parametric Stopwatch Automata (PSA): we generate a PSA model from a high-level description of the system, and then we apply the Inverse Method to obtain all possible behaviours of the system. Both techniques have been implemented in two software tools, and they have been compared with classical holistic analysis on two meaningful test cases. The results show that the analytic method provides results similar to classical holistic analysis in a very efficient way, whereas the PSA approach is slower but covers the entire space of solutions.