Fine-Grained CPU Power Management Based on Digital Frequency Divider

Dynamic voltage and frequency scaling (DVFS) is a widely used method to improve the energy efficiency of the CPU. Reducing the voltage and frequency during memory-intensive workloads can minimize power consumption without affecting performance, thereby improving overall energy efficiency. A finer-grained DVFS strategy leads to better energy efficiency. However, due to the limitation of voltage regulators, the implementation granularity of the current DVFS strategies is 100 μs or more. This paper proposes that managing the CPU’s power through a more fine-grained load-aware approach can improve CPU energy efficiency, even with limitations of the voltage regulators. This paper adds a more fine-grained dynamic frequency divider to the DVFS system. This mechanism can improve the processor’s energy efficiency in scenarios where DVFS does not take effect. This paper also proposes a DVFS management strategy based on finer-grained sampling. In order to improve the accuracy of performance estimation, we enhanced the state-of-the-art CRIT method to complete accurate memory time estimation in a shorter interval. The power management strategy was verified on the ChampSim and McPAT simulating platforms. In the SPEC CPU 2017 benchmark, this work saves an average of 16.36% energy consumption and improves energy efficiency by 13.57%. Compared with the state-of-the-art CRIT of 9.77% and 6.79%, this work improved energy consumption and efficiency by 6.20% and 6.35%, respectively. This method brings a 2.04% performance reduction, only a 0.16% drop in performance compared to CRIT.