PowerTop recommendations: an evaluation

[Colin Ian King]

Hi there, more test results..

As part of the Kernel Power Management blueprint 
https://blueprints.launchpad.net/ubuntu/+spec/hardware-p-kernel-power-management 
I was given a task to measure various PowerTop recommended "tunables" to 
see how beneficial they are.

I've run some extensive tests on two typical mobile platforms and 
analysed the power consumed of "Bad" and "Good" tunable power states for 
various devices, controllers and kernel tunables.  There is a lot of 
data, some of it provides a very clear indication of large power saving 
gains, some is less clear, and some settings are quite unexpected as 
they seem to consume more power than expected in a power saving state(!)

The data (as a LibreOffice spreadsheet) + results can be found in:

http://zinc.canonical.com/~cking/power-benchmarking/powertop-good-bad-recommendations/

In summary:

For best power consumption, we should have some pm-utils power.d scripts 
to put the following device controllers into a low power state:

         * Webcam
         * Audio
         * DRAM
         * Ethernet
         * Wifi
         * Bluetooth
         * SATA link
         * MMC/SD

Comments and questions most welcome.

Colin