Bounded energy allocation and scheduling for real-time Embedded Systems

Abstract

For energy-constrained real-time embedded systems, the power-delay tradeoff property of Volta ge-Clock Scaling (VCS) needs to be carefully considered in scheduling real-time tasks for meeting strict timing requirements. In addition, non-real-time tasks require minimized response times. Thus, a bounded energy allocation model should be adopted to solve a combination of optimization objectives in systems having mixed hard and soft real-time tasks. In this paper, we propose an energy sharing model that allocates the energy budget among hard and soft real-time tasks, exploiting the interplay between utilization and energy consumption in VCS-based earliest-deadline-first scheduling (VCS-EDF). Also a dynamic scheduling is presented which is designed to reduce energy consumption by switching between two scheduling policies and utilizing an explicit pattern of event occurrences at run-time. Through simulations, we show that this Dual-Policy Dynamic Scheduling can outperform in the reduction of energy consumption while introducing small delay in average response time of non-real-time tasks.