Lifetime-aware real-time task scheduling on fault-tolerant mixed-criticality embedded systems

In recent years, the design of mixed-criticality embedded systems suffering from transient faults has attracted much attention. From the perspective of system users, it is desirable to optimize system lifetime while meeting all design constraints. Existing task scheduling algorithms cannot be utilized to maximize the lifetime of mixed-criticality embedded systems since they do not take into account the impact of providing transient fault tolerance on system lifetime. This paper investigates the problem of prolonging the lifetime of mixed-criticality embedded systems on a uniprocessor equipped with dynamic voltage and frequency scaling (DVFS) technique. The transient faults and thermal cycling incurred permanent faults are simultaneously considered in the system lifetime optimization under the constraints of safety requirements and schedule timeliness. A mixed-integer linear programming (MILP) formulation is first presented to deal with the task scheduling problem. Since the MILP method is a time-consuming solution for large-scale systems, a cross-entropy method based heuristic is then proposed to achieve a better tradeoff between the system lifetime achieved by the derived task schedule and the runtime consumed to generate the task schedule. Experiments based on synthetic and real-world benchmarks are conducted, and simulation results demonstrate that the proposed heuristic improves system lifetime by up to 32.73% with acceptable runtime as compared to benchmarking methods.