Energy-Efficient Static Priority and Speed Assignment for Real-Time Tasks with Non-deterministic Release Times

Dynamic Voltage Scaling (DVS) has been widely used for decreasing the dynamic power dissipation of processors. For real-time systems, DVS techniques have been developed that permit to meet the timing constraints of multiple real-time tasks and at the same time reduce the overall dynamic energy consumption. Known methods for static priority DVS scheduling are, however, either restricted to simple periodic/sporadic task release patterns or presume full a priori knowledge of task release times. Moreover, none of the present approaches considers the optimization of task priorities for reducing the energy consumption. In this paper we explore how to determine the static priorities and individual execution speeds (supply voltages) of multiple tasks with non-deterministic release times bounded by arrival curves such that the energy consumption is reduced and the real-time constraints are met. The result are different heuristics for the design of DVS-based real-time systems with static priorities. We show that the proposed methodology leads to energy-efficient system designs and demonstrate the applicability of the approach by means of experiments.