Real-time loop scheduling with energy optimization via DVS and ABB for multi-core embedded system

Dynamic Voltage Scaling (DVS) is an effective technique to reduce energy consumption of processors by dynamically adjusting the operational frequency and supply voltage. However, with feature sizes shrinking, the achievable power saving by DVS is becoming limited as the leakage power increases exponentially. Adaptive Body Biasing (ABB) is an effective technique to reduce leakage power by increasing the circuit's threshold voltage via body biasing. In this paper, we propose a novel real-time loop scheduling technique to minimize both dynamic and leakage energy consumption via DVS and ABB for applications with loops considering voltage transition overhead. The proposed algorithm, EOLSDA (Energy Optimization Loop Scheduling with DVS and ABB), is designed to repeatedly regroup a loop based on rotation scheduling [4,5] and decrease the energy consumption via DVS and ABB within a timing constraint. We conduct experiments on a set of DSP benchmarks based on the power model of 70nm technology. The results show that our technique achieves big energy saving compared with list scheduling [8] and the algorithm in [11].