Dynamically reducing overestimated design margin of MultiCores

Abstract

MultiCore processor is one of the promising techniques to satisfy computing demands of the future consumer devices. However, MultiCore processor is still threatened by increasing energy consumption due to PVT (Process-Voltage-Temperature) variations. They require large design margins in the supply voltage, resulting in large energy consumption. The combination of DVS (Dynamic voltage scaling) technique and Canary FF (flip-flop), named Canary-DVS, has been proposed to eliminate the overestimated voltage margin but has only been evaluated under the assumption of typical delay. This paper considers C2C (Core-to-Core) variations and evaluates how Canary-DVS eliminates the energy waste under the practical assumption of delay variations. We adopt Canary-DVS to a commercial processor, Toshiba's quad-core Media embedded Processor (MeP). From Monte Carlo simulations, it is found that energy is reduced by 18.6% on average and there are not any noticeable discrepancies from the typical situations, when 0.064 of σ/μ value is assumed in gate delay.