Open Source Summit + ELC Europe 2019

Energy-efficiency is about optimizing the usage of energy with the goal to reduce it to the acceptable minimum.

Some Linux kernel features have been introduced with energy-efficiency in mind. It is the main goal of CPU idle time management, CPU performance scaling, PM-runtime and system-wide PM. Unfortunately, these features are often avoided out of concerns that they may prevent systems from achieving optimum performance or they are underutilized.

Needless to say, it does matter whether or not the kernel's energy-efficiency features are in use, however. The battery life of portable systems is affected by that directly, data center power budgets are not unlimited and, generally speaking, avoidable costs should not be paid, especially if they are environmental as well as financial. In this particular case it should be possible to avoid paying them, by enabling the features in question and controlling them with the help of interfaces provided for that, which I am going to explain.