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Fedora 14

Power Management Guide

Managing power consumption on Fedora

Edition 1

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Red Hat Inc.

Don Domingo

Red Hat Engineering Content Services

Rüdiger Landmann

Red Hat Engineering Content Services

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Abstract
This document explains how to manage power consumption on Fedora 14 systems effectively. The following sections discuss different techniques that lower power consumption (for both server and laptop), and how each technique affects the overall performance of your system. Please note: This document is still under development, is subject to heavy change, and is provided here as a preview. The content and instructions contained within should not be considered complete, and should be used with caution.

Preface
1. Document Conventions
1.1. Typographic Conventions
1.2. Pull-quote Conventions
1.3. Notes and Warnings
2. We Need Feedback!
1. Overview
1.1. Importance of Power Management
1.2. Power Management Basics
2. Power management auditing and analysis
2.1. Audit and analysis overview
2.2. PowerTOP
2.3. Diskdevstat and netdevstat
2.4. Battery Life Tool Kit
2.5. Tuned and ktune
2.5.1. The tuned.conf file
2.5.2. Tuned-adm
2.6. UPower
2.7. GNOME Power Manager
2.8. Other means for auditing
3. Core Infrastructure and Mechanics
3.1. CPU Idle States
3.2. Using CPUfreq Governors
3.2.1. CPUfreq Governor Types
3.2.2. CPUfreq Setup
3.2.3. Tuning CPUfreq Policy and Speed
3.3. Suspend and Resume
3.4. Tickless Kernel
3.5. Active-State Power Management
3.6. Aggressive Link Power Management
3.7. Relatime Drive Access Optimization
3.8. Power Capping
3.9. Enhanced Graphics Power Management
3.10. RFKill
3.11. Optimizations in User Space
4. Use Cases
4.1. Example — Server
4.2. Example — Laptop
A. Tips for Developers
A.1. Using Threads
A.2. Wake-ups
A.3. Fsync
B. Revision History