On the design of energy-efficient service rate control mechanisms: CPU frequency control for Linux

A simple model of service rate control system is presented that may be used to design energy-aware control rules for the processors capable of adjusting their operating capabilities to the observed workload. The model exploits a bi-objective processing performance index aggregating the cost of energy consumption and the cost of service delivery. An approximate solution to the related stochastic optimal control problem is presented. Based on the obtained results a collection of CPU frequency control governors for the Linux kernel was designed and implemented. Performance of the designed controllers was next experimentally compared to the performance of the Linux cpufreq_ondemand governor. The obtained results suggest ways to improve efficiency of the Linux kernel CPU frequency control mechanisms. A brief description of the experimental environment is given.