Dynamic voltage scaling (DVS) is arguably rhe most eflective energy reduction technique. 7kle multiple-voltage DVS system, which can operate only at pre-determined discrete voltages, are practical and hove been well studied. However, one important unsolvedproblem is how many levels and at which values should voltages be implemented on 4 multiple-voltage DVS system to achieve the marimum energy saving. We refer this as the voltage set-up problem. In this paper, ( I ) we derive analytical solutions for dual-voltage system. (2) For the general case that does not have analyrir solutions, we develop efficient numerical methods. ( 3 ) We demonstrote how to apply the proposed algorithms on system design. (4) Interestingly, the erperimenrnl results suggest that the multiple-voltage DVS system, when the voltages are set up properly, can reach DVS technique's full potential in energy saving. Specifically, on the design of an ad hoc applicarionspecific system and the design of the MPEG video encoder, we find that the best single-voltage systems consume 150% and 20% more energy than the right theoretical lower bounds, respectively. However, our approach gives dual-, 3 . . and 4-voltage DVS system settings that are only 17.6%. 4.9%. and 2.6% for the ad hoc system, and 4.0%. 1.1%. and 0.2% for the MPEG video encoder. over the same lower bounds.
The voltage-setup problem is first formulated in REF to determine the number of levels and at which values voltages should be implemented to deliver the optimal energy-saving performance for a specific application.
Approaching the maximum energy saving on embedded systems with multiple voltages