EEDS/spl I.bar/NR: an online energy-efficient I/O device scheduling algorithm for hard real-time systems with non-preemptible resources

The challenge in conserving energy in embedded real-time systems is to reduce power consumption while preserving temporal correctness. Much research has focused on power conservation for the processor, while power conservation for I/O devices has received little attention. In this paper, we analyze the problem of online energy-aware I/O scheduling/or hard real-time systems based on the preemptive periodic task model with non-preemptible shared resources. We extend the concept of device slack to support non-preemptible shared resources; and propose an online energy-aware I/O scheduling algorithm: energy-efficient device scheduling with non-preemptible resources (EEDS_NR). The EEDS_NR algorithm utilizes device slack to perform device power state transitions to save energy, without jeopardizing temporal correctness. An evaluation of the approach shows that it yields significant energy savings