Dynamic Constraints for Mixed-Criticality Systems

We define quality of service requirements for mixed-criticality systems based on min-plus algebra rather than discrete criticality levels. The requirements (1) unify a spectrum of weakly-hard real-time requirements with strongly-hard real-time and soft real-time as extreme cases and (2) support dynamic tuning of task importance. The paper elaborates the relation to mixed-criticality scheduling theory and weakly-hard real-time systems. The supported timing requirements, computational complexity, and scheduling feasibility are discussed.