Reduce Linux power consumption

Great article by IBM, for those working with Red HAT Linux.

"In this series, learn how to tune your Linux-based IBM System x server for power efficiency. You'll learn about the in-kernel governors and their settings and how to use them; you'll also see the effects of the tuned governors on a power performance and e-commerce workload. The examples are based on a System x server running Red Hat Enterprise Linux version 5.2 (RHEL 5.2), but the same guidelines apply to any of the 2.6.x kernels, as well as any processor type that supports frequency scaling.

Part 1 introduces the components and concepts you'll need to tune your system for power efficiency, including the Linux CPUfreq subsystem, C and P states, and the five in-kernel governors.

Part 2 gives more details on the general settings of the Linux CPUfreq subsystem and the five in-kernel governors—performance, powersave, userspace,ondemand, and conservative—and their settings.

Part 3 compares the performance of the five in-kernel governors in both a tuned and an untuned state to show you what results you can achieve by power tuning your system."