Features/PowerManagementF17

= Feature PowerManagementF17 =

Summary
The goal of SIGs/PowerManagement is to improve the current state of power management in userspace. For Fedora 17 our plan is to extend and improve tuned functionality.

Owner

 * Name: Jaroslav Škarvada


 * Email: jskarvad AT redhat.com

Current status

 * Targeted release: Fedora 17
 * Last updated: 2012-03-20
 * Percentage of completion: 100%

Detailed Description
Tuned package contains a daemon that tunes system settings statically and dynamically according to selected profile (e.g. performance, low latency, low power consumption). In the past, profiles could be changed only from command line. Later, matahari support was implemented for remote tuning capability. Now, we would like to add dbus interface for better desktop integration. The new interface will also support "on demand" tuning, i.e. applications could signal it's requirements via dbus that would be taken into account by tuned. Next, we would like to improve current tuned profiles, add capability for creation / management of custom profiles, provide tighter integration with powertop and more.

Benefit to Fedora
The planned tuned update will extend the PM tuning capability. Namely it will bring:


 * dbus interface for better desktop integration and "on demand" tuning,
 * tighter integration with powertop and creation of custom profiles from powertop reports,
 * custom profiles management,
 * improved formula for scomes score calculation,
 * improved tuned profiles for better performance / higher power savings:
 * addition of KVM host/guest tuned profiles,
 * support for Radeon power savings,

Scope

 * tuned needs to be reworked. So far the profile switching was performed by full restarts - this needs to be rewritten (some code changes were already made in SCM experimental branch),
 * powertop needs to be patched (patch was accepted by upstream).

How To Test
We plan to test this feature during PowerManagement test day. Detailed instructions will be provided later on the test day wiki (similary to our previous test days). Currently known details:


 * 1) Any PC can be used for testing. For power consumption comparison (optional part), a) external wattmeter or b) laptop with functional ACPI will be needed. Users without this equipment can skip the optional part.
 * 2) Live-CD image with all preinstalled SW and tools will be provided. These tools will be also available from special test repository.
 * 3) Semi automatic and manual test cases with detailed instructions will be prepared. At least following test cases will be utilised:
 * 4) * tuned profiles switching via command line and dbus,
 * 5) * creation of custom tuned profiles from existing profiles,
 * 6) * creation of tuned profiles for aggresive power savings from powertop suggestions,
 * 7) * removal of custom profiles,
 * 8) * comparison of tuned profiles efficiency for various use cases (measurement / automatic benchmark).

User Experience
With default config the feature will be invisible to users. They will be able to take advantage of it when they start tuning their systems and using tuned.

Dependencies

 * tuned - developed by us
 * powertop - maintained by us

Contingency Plan
There is no risk if this feature wouldn't be completed by deadline. In such case we will revert to the previous release behaviour.

Documentation
Man pages and Fedora power management guide will be updated accordingly.

Release Notes
There shouldn't be anything specific. Some highlights could be selected from the 'Benefit to Fedora' chapter.

Comments and Discussion

 * See Talk:Features/PowerManagementF17