Towards the Design of Certifiable Mixed-criticality Systems

Many safety-critical embedded systems are subject to certification requirements; some systems may be required to meet multiple sets of certification requirements, from different certification authorities. Certification requirements in such "mixed-criticality" systems give rise to some interesting scheduling problems, that cannot be satisfactorily addressed using techniques from conventional scheduling theory. In this paper, we propose a formal model for representing such mixed-criticality workloads. We demonstrate the intractability of determining whether a system specified in this model can be scheduled to meet all its certification requirements. For dual-criticality systems - systems subject to two sets of certification requirements - we quantify, via the metric of processor speedup factor, the effectiveness of 2 techniques (reservation-based scheduling and priority-based scheduling) that are widely used in scheduling such mixed-criticality systems.