Real-time task scheduling for energy-aware embedded systems

We present a new approach for scheduling workloads containing periodic tasks in real-time systems. The proposed approach minimizes the total energy consumed by the task set and guarantees that the deadline for every periodic task is met. Energy is a scarce resource for embedded systems, and energy consumption must be carefully balanced against real-time responsiveness. As embedded software becomes a larger component of system-on-a-chip design, energy management using the operating system becomes increasingly important. We present a mixed-integer linear programming model for the NP-complete scheduling problem and solve it for moderate-sized problem instances using a public-domain solver. For larger task sets, we present a novel low-energy earliest-deadline-first (LEDF) scheduling algorithm and apply it to two real-life task sets. We also present extended-LEDF (E-LEDF), a modified version of LEDF that considers more practical scenarios. Our results show that energy can be conserved in embedded real-time systems using energy-aware task scheduling. (C) 2001 The Franklin Institute. Published by Elsevier Science Ltd. All rights reserved.