A generic approach for the certified schedulability analysis of software systems

Embedded systems often need to react in a timely manner. Life-critical or mission-critical ones require assurance that they comply with these real-time requirements. In particular, schedulability analysis is both essential and difficult to get right. Formal methods can help as they are a powerful tool for ensuring properties with the highest assurance level. We describe a case study for the FPP and EDF policies providing end-to-end assurance by connecting the schedulability analysis tool Prosa and the real-time OS kernel RT-CertiKOS, both using the Coq proof assistant to prove their results. Analyzing precisely the key ideas underlying this connection, we improve it to make it more generic and reduce the associated proof burden. We thus sketch a refined method which allows for providing formal schedulability guarantees to other OSes or low-level components with minimal effort.