Integrated Device Scheduling and Processor Voltage Scaling for System-wide Energy Conservation

The challenge in conserving energy in embedded real-time systems is to reduce power consumption while preserving temporal correctness. Previous research has focused on power conservation for either the processor or I/O devices alone. The system-wide energy conservation has received little attention. In this paper, we analyze the problem of system-wide energy-efficient scheduling for hard real-time systems based on the preemptive periodic task model with non-preemptive shared resources. We propose an online system-wide energy-efficient scheduling algorithm Systemwide Energy-Aware EDF (SYS-EDF), which integrates Dynamic Power Management (DPM) for I/O devices and Dynamic Voltage Scaling (DVS) for the processor. An evaluation of SYS-EDF shows that it yields significant energy savings with respect to DVS alone or DPM alone techniques.