Hi, current powertop git has two new features, that at this time require kernel patches.
Feature 1: Detecting who is keeping the disk busy A spinning disk takes between 0.5W and 1W of power,and on laptops the BIOS will have configured an appropriate timeout into the disk to spin down[*]. So the trick is to keep the disk idle, which in turn means catching who's writing to the disk. The powertop -git tree has code to use the perf system in the kernel to find the guilty processes. Feature 2: Showing how busy the audio codecs are PowerTOP already has the feature to suggest to enable HDA audio power saving; however we did not yet show how effective this power saving was. With the help of a patch created by Takashi Iwai (SuSE/Alsa team) we now report the utilization (in terms of power saving vs active). PowerTOP will report the utilization in "-d" mode; in addition if the utilization is non-zero, it will also provide a suggestion during the "normal" mode. The kernel patches needed to report these are on the way to the Linux kernel; if there's enough demand I'd be happy to post them to the PowerTOP mailing list separately. [*] The actual power savings setting of the disk is a tricky one: set it too aggressive and the lifetime of the disk might be shortened due to frequent start/stop cycles; set it not aggressive enough and the lifetime of the disk might be shortened due to running warmer. This is a tricky, disk and hardware specific balance that also ties into the warranty. However, some distributions think they can know this better than the hardware vendor and will poke values into the disk that they consider more appropriate. In case these values are less aggressive, your power saving will also likely be less than the 0.5W-1W range. _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
