Using Cpufreq on Linux Servers to Manage Power Consumption

One of the most effective ways to reduce power consumption and heat output on a server system is the cpufreq subsystem. Cpufreq, also referred to as CPU frequency scaling or CPU speed scaling, is the infrastructure in the Linux kernel space that enables users to scale the CPU frequency in order to save power.

CPU scaling can be initiated in different ways:

• Automatically based on the system loading
• In response to ACPI events
• Automatically by the hardware
• Manually by userspace programs

This paper show users how to enable cpufreq drivers through correct BIOS settings, and introduces the interface of the cpufreq subsystem that allows flexible control through processor frequency. In addition, this document offers a guide to users, showing them how to choose proper drivers based on different scenarios.

Introduction
Cpufreq subsystem
Using the acpi-cpufreq driver
Using the intel-pstate cpufreq driver
Driver selection based on application scenarios
Autonomous P-states
References

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Related product families

Product families related to this document are the following:

• Processors
• Red Hat Enterprise Linux
• SUSE Linux Enterprise Server