PowerTop

The 2.0 codebase extensively uses the kernel "perf" infrastructure to give much more accurate data for the various reports. Another major feature of the 2.0 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. A new power estimation engine is able to give an estimate of how much power individual devices and processes in the system are consuming. This release requires a relatively new kernel to work properly (2.6.37, but 2.6.36 will also work).

PowerTOP now supports Runtime Device Power Management. Support for reporting which application keeps the disk from powersaving mode was added. Support for reporting AHCI Link power management statistics was added. Support for Audio power saving statistics was added. Support for "Turbo Mode" on Intel processors was added. Support for multiqueue network interface cards was added. Support for device runtime power management was added. New kernel configuration suggestions are made. Lots of small bugs were fixed. Valgrind cleanups were made. Much more was done.

Calculations were fixed for systems that vary in
power draw proc information. Compilation with PIC
was fixed. An EOF at input was fixed. The polling
hint now refers to /dev/cdrom instead of
/dev/scd0. mwait usage is displayed. The
--version|-v option was added. A spelling error in
tips was fixed.

On sufficiently new CPUs (and Linux kernel 2.6.25), Powertop now reports which C-states the CPU and BIOS report and support. Support for reading C-state information via sysfs was added. Support for sysfs power supply class was added. Support for the "P" key to show the PIDs of the processes when possible was added. Support for Intel 4965 wireless power saving mode was added. Powertop now shows USB suspend statistics as a low priority hint for busy devices and general USB suspend statistics in dump mode.

Powertop now reports USB activity. Support for
mac80211 based wireless powersaving and the newly
reported interrupt events in 2.6.24-rc was added.
Bluetooth inactivity detection was improved.