Exploring Energy Reduction in Future Technology Nodes via Voltage Scaling with Application to 10nm

Abstract

Voltage and frequency downscaling is a well-known scheme in order to reduce the energy consumption of a computer system. However, the quantity of the saved energy first depends on the utilized technology node. Also, when the voltage level is below the safe margin, instructions need to be re-executed due to voltage related faults which can present additional energy overheads thus nullifying the expected energy gains from the lower voltage. Moreover, both fault recovery and frequency reduction impacts the performance of the application. In this study, we first evaluate the error rate of several sub-circuits (i.e. functional units) at the n10 future technology node. In order to reduce the performance impact, we reduce the voltage and frequency of each sub-circuit at a fine granularity while we keep the frequency of the rest of the system in the nominal voltage level. In this way, in an out-of-order architecture instruction level parallelism can mask the performance impact of a relatively slow functional unit. According to our evaluations, the energy consumption of functional units can be reduced up to 92% with only 8% performance degradation.