The Optimal Profile-Guided Greedy Dynamic Voltage Scaling in Real-Time Applications

Compiler-directed dynamic voltage scaling (DVS) is an effective low-power technique in real-time applications, where compiler inserts voltage scaling points in a real-time application, and supply voltage and clock frequency are adjusted to the relationship between the remaining time and the remaining workload at each voltage scaling point. Greedy dynamic voltage scaling is one of the voltage adjustment schemes, where the slack time of current section is completely used to reduce the clock frequency of next section. In this paper we present the analytical model of the greedy scheme, and by simulations using the analytical model, we find out that the greedy scheme obstructs itself from effectively utilizing the slack times. So we propose a profile-guided greedy voltage adjustment scheme directed by the optimal realtime voltage scheduling in the most frequent execution case. We show by simulations that the new voltage adjustment scheme obtains the largest reduction of energy consumption of all the current representative schemes.