Linux Power Management: Are You Doing it Right?

Devices operating on battery power need effective power management: anything you can do to reduce power usage will increase battery life. Even for devices running on mains power, better power managements has benefits in reducing the need for cooling and lower energy costs. In this talk, I focus on the beneficial effects you can get from using the Linux power management infrastructure to the full. I introduce the four principles of power management: don't rush if you don't have to; don't be ashamed of being idle; turn off things you are not using; and sleep when there is nothing else to do. In the Linux kernel, these are implemented by the following subsystems: CPUFreq; CPUIdle; Runtime PM and system sleep. I show the effect of each of these techniques on a typical embedded development board and give you some guidelines that you can apply to your own projects.