Real-time loop scheduling with leakage energy minimization for embedded VLIW DSP processors

In this paper, we develop a novel real-time instruction-level loop scheduling technique to reduce leakage energy consumption for applications with loops on VLIW architecture. We first prove that the scheduling problem with the minimum leakage energy consumption within a timing constraint is NP-complete. Then, LEMLS (Leakage Energy Minimization Loop Scheduling) algorithm is designed to repeatedly regroup a loop based on rotation scheduling [3], and decrease leakage energy integrating with leakage power reduction mechanism. We conduct experiments on a set of DSP benchmarks based on the power model of the VLIW processors in [12]. The results show that our algorithm achieves significant leakage energy saving compared with list scheduling and the algorithm in [19].