Adaptive scheduling of fault-tolerant parallel programs with timing constraints

We propose an adaptive preemptive scheduler for scheduling external sporadic tasks in a multiprocessor real-time system. We first present a pre-run-time scheduler to schedule a fault-tolerant parallel program with precedence constraints. Every task in the parallel program consists of two subtasks, namely, mandatory and optional. During run-time we optimally schedule the external tasks using the proposed adaptive scheduler. The scheduler removes the minimum number of optionals from the pre-run-time schedule to accommodate the external tasks. The performance of the system due to use of fault-tolerance is also demonstrated.