Energy aware non-preemptive scheduling for hard real-time systems

Slowdown based on dynamic voltage scaling (DVS) provides the ability to perform an energy-delay tradeoff in the system. Nonpreemptive scheduling becomes an integral part of systems where resource characteristics makes preemption undesirable or impossible. We address the problem of energy efficient scheduling of nonpreemptive tasks based on the earliest deadline first (EDF) scheduling policy. We present the stack based slowdown algorithm that builds upon the optimal feasibility test for nonpreemptive systems. We also propose a dynamic stack reclamation policy to further enhance energy savings. Simulation results show on an average 15% energy savings using static slowdown factors and 20% savings with dynamic slowdown, over known slowdown techniques.