From Fedora Project Wiki

Power Management improvements for Fedora 15


The goal of SIGs/PowerManagement is to improve the current state of power management in userspace. For Fedora 15 the plan is to improve the power monitoring and power profiling capabilities by upgrading PowerTOP to the 2.x branch. We also would like to extend and improve the functionality of tuned and update pm-utils to the latest version.



  • Jaroslav Škarvada <> (package maintainer of powertop and pm-utils, measurement/benchmarking)
  • Jan Včelák <> (tuned developer / maintainer)

Current status

  • Targeted release: Fedora 15
  • Last updated: 2011-03-22
  • Percentage of completion: 100%

Detailed Description

PowerTOP is a tool that finds the software components that make your computer use more power than necessary while it is idle. PowerTOP 2.x is complete rewrite of the 1.x code base. It extensively uses the kernel "perf" infrastructure to give much more accurate data. Another major feature of the 2.x code base is that the power behavior of the various devices in the system is prominently tracked and displayed, so that it's clear which devices are problematic in terms of power behavior. One of the more experimental features of the 2.0 codebase is a power estimation engine, which, after calibration and getting sufficient measurement points, is able to give an estimate of how much power individual devices and processes in the system are consuming. Currently the first beta was released by upstream.

The tuned package contains a daemon that tunes system settings dynamically to balance the power consumption and performance. It also performs various kernel tunings according to selected profile. The new version of tuned brings several bug fixes, improvements and profiles updates for better efficiency.

The pm-utils package contains utilities and scripts useful for tasks related to power management. We have synced it to the latest upstream version and updated the contributed bug reporting script.

Benefit to Fedora

The PowerTOP 2.x announcement can be found at: The highlights for Fedora users are:

  • redesigned, tab based, user interface
  • improved accuracy
  • power estimation engine
  • ability to create HTML reports


  • updated profiles for better efficiency
  • EEEPC: added dynamic FSB switching (AKA SHE) according to CPU load (laptop-battery-powersave profile)
  • added new man pages


  • updated to latest version
  • improved bug reporting script to give more information about the user system - it helps the maintainer to better handle the bug reports about any suspend problems


The powertop and tuned packages need to be updated in rawhide. The pm-utils was already updated.

How To Test


  • start it and wait to collect data
  • cycle through tabs, check all reports for inconsistencies
  • accept tuning suggestions, check if it were really applied through sysfs


  • service tuned start
  • tuned-adm profile laptop-battery-powersave
  • run benchmark (BLTK), kernel compilation
  • tuned-adm profile throughput-performance
  • run benchmark and compare results


  • suspend machine by: pm-suspend, check if resumes correctly
  • hibernate machine by: pm-hibernate, check if resumes correctly
  • run and check if the report was correctly generated

We are going to prepare a test day with complete instructions, benchmarks, tools.

User Experience

Users should notice the new redesigned PowerTOP interface and new functionality such as the power estimation engine. Other improvements are not directly visible without measuring. So in order to really see the effect you'll either need a laptop and run it on battery or a power meter that is hooked between your system and the power line.


  • To enable all functionality of PowerTOP 2.0, kernel-2.6.37 or newer is required.

Contingency Plan

  • Revert to PowerTOP 1.x or provide the legacy 1.x binary.
  • Other updates shouldn't break things.


Announce of the PowerTOP 2.0 Beta

Release Notes

No need for release notes entry.

Comments and Discussion