Value-based scheduling of distributed fault-tolerant real-time systems with soft and hard timing constraints

We present an approach for scheduling of fault-tolerant embedded applications composed of soft and hard real-time processes running on distributed embedded systems. The hard processes are critical and must always complete on time. A soft process can complete after its deadline and its completion time is associated with a value function that characterizes its contribution to the quality-of-service of the application. We propose a quasi-static scheduling algorithm to generate a tree of fault-tolerant distributed schedules that maximize the application's quality value and guarantee hard deadlines.