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== Documentation ==
== Documentation ==
=== Tuned-adm ===
This new tool allows an administrator to easily switch between different systemwide settings for power (and performance) tuning for his system. Settings can be added, edited or deleted depending on the specific needs or circumstances of the system or administrator.
The following settings are included by default in the current version of tuned:
* default
** Default settings with which tuned and ktune come initially
* desktop-powersave
** Very light powersaving profile directed at desktop systems.
* server-powersave
** Very light powersaving profile directed at server systems.
* laptop-ac-powersave
** Medium powersaving profile directed at laptops running on AC.
* laptop-battery-powersave
** Strong powersaving profile directed at laptops running on battery. This profile will affect the overall performance of the system as a tradeoff for typically longer running time on battery power.
* throughput-performance
** Sever profile for typical througput performance tuning.
* latency-performance
** Sever profile for typical latency performance tuning.
=== scomes ===
=== scomes ===

Revision as of 11:38, 21 October 2009


Power Management improvements for Fedora 12


Our goal is the improvement of power management especially in regard to userland. This project is based on measurement and statistic of power consumption mainly on laptops. We are trying to locate the main power greedy applications by measuring with new tools, which have been introduced in our project. For Fedora 12 the plan is to improve and extend the functionality of tuned, merge it with ktune from RHEL 5 and introduce a new and easy way to switch between various predefined and extendible tuning settings for your system.


  • Phil Knirsch <pknirsch@redhat.com> (Lead, tuned, monitoring, documentation)
  • Jiri Skala <jskala@redhat.com>(BLTK packager, pm-utils maintainer)
  • Marcela Maslanova <mmaslano@redhat.com> (system profile switcher)
  • Petr Lautrbach <plautrba@redhat.com> (scomes, system profile switcher)
  • Jan Scotka <jscotka@redhat.com> (QA coverage)
  • Karel Volny <kvolny@redhat.com> (QA coverage)

Current status

  • Targeted release: Fedora 12
  • Last updated: 2009-08-18
  • Percentage of completion: 100%

Detailed Description

With Fedora 11 we introduce a new daemon called tuned. The goal now is to extend it's functionality and merge it with a tool we developed for Red Hat Enterprise Linux 5 called ktune as well as introduce a new and easy way to switch between various predefined and extendible tuning settings for your system.

Of course auditing wakeups and disk/network IO is still ongoing for Fedora 12 as well.

Benefit to Fedora

Simple: On average use less power for turned on machines while not affecting user experience (a lot ;)).


  • Review and fix behaviour of typical applications in a full installed Fedora in regard to: [IN PROGRESS]
    • CPU wakeups
    • Disk IO
    • Network IO
  • Extend tuned
    • Integration of ktune and tuned: Static vs. dynamic tuning parts + performance vs. power tuning options [100% DONE (scheduled for more tests during testday Oct 22)]
    • New monitoring and tuning plugin for CPUs (using PM-QOS for CPUs) [100% DONE]
    • New disk tuning algorithm for a more gradual tuning [100% DONE (scheduled for more tests during testday Oct 22)]
  • System tuning configuration and profiles [100% DONE (scheduled for more tests during testday Oct 22)]
    • Introduce new CLI to allow switching between various predefined settings
    • Allow creating / editing / deleting profiles
  • New tool to measure improvements to system configuration changes or application changes: http://fedoraproject.org/wiki/Features/PowerManagement/scomes [100% DONE]

Tests & Test Day

We prepare Fedora test day on the 22nd of October 2009. There we want to give users the chance to test all the the new features coming in Fedora 12. The results will be compared with previous test day that took place in April 2009.

Test Day 2009-10-22

User Experience

As power saving is not really visible without a measuring it the effects will not be directly visible. So in order to really see the effect you'll either need a laptop and run that on battery power or a wattmeter that is hooked between your system and the power line.


tuned base package now requires kobo for the tuned-adm tool.

Contingency Plan

Need to make sure to test the more aggressive power saving features if they break on common hardware and back it out in case they do or make some form of black/whitelist for know cases.



Scomes is a new systemtap script that can be used to measure the effectiveness of system configuration changes and/or code changes to applications.

The goal was to:

  • Measure amount of system resources consumed by the program.
  • Compare different programming techniques in view of system resources.
  • Create programming tips based on these results.

More info on how it works and how to use it and some examples can be found here:



Release Notes

In order to allow users to monitor the behaviour of their systems and to improve power consumption in general, several improvements were done for Fedora 12:

  • Improved tuned service to dynamically adapt system settings to the current use
  • New static tuning service available called ktune as part of tuned
  • New configuration switch commandline tool called tuned-adm, coming with several predefined but editable system setting profiles
  • New systemtap tool called scomes to measure amount of system resources consumed by a program

Users of Fedora 12 should therefore see a reduction in power usage of their system.

Comments and Discussion