Predicting Performance Impact of DVFS for Realistic Memory Systems

Dynamic voltage and frequency scaling (DVFS) can make modern processors more power and energy efficient if we can accurately predict the effect of frequency scaling on processor performance. State-of-the-art DVFS performance predictors, however, fail to accurately predict performance when confronted with realistic memory systems. We propose CRIT+BW, the first DVFS performance predictor designed for realistic memory systems. In particular, CRIT+BW takes into account both variable memory access latency and performance effects of prefetching. When evaluated with a realistic memory system, DVFS realizes 65% of potential energy savings when using CRIT+BW, compared to less than 34% when using previously proposed DVFS performance predictors.