Published: Thursday, Jan 31, 2013 Last modified: Wednesday, Oct 2, 2024

Putting Powertop tunables in a systemd format will probably be blogged by Lennart, though here goes. Prompted by the legendary Power regressions thread.

Using PowerTOP version v2.7:

sudo powertop -r powertop.html

You should get a report like http://s.natalian.org/2015-07-08/powertop.html

Use the td:first-child { display: none; } trick to be able to copy and paste the second column.

You will get something like:

iw dev wlan0 set power_save off
echo 'min_power' > '/sys/class/scsi_host/host0/link_power_management_policy';
echo '0' > '/proc/sys/kernel/nmi_watchdog';
echo '1500' > '/proc/sys/vm/dirty_writeback_centisecs';
echo '1' > '/sys/module/snd_hda_intel/parameters/power_save';
echo 'auto' > '/sys/bus/usb/devices/3-1/power/control';
echo 'auto' > '/sys/bus/pci/devices/0000:0e:00.0/power/control';
ethtool -s net0 wol d;

Which I save into a tunables.txt, this is mine for example.

Which you need to convert like so in systemd’s /etc/tmpfiles.d/power-savings.conf:

w /sys/class/scsi_host/host0/link_power_management_policy - - - - min_power
w /proc/sys/kernel/nmi_watchdog - - - - 0
w /proc/sys/vm/dirty_writeback_centisecs - - - - 1500
w /sys/module/snd_hda_intel/parameters/power_save - - - - 1
w /sys/bus/usb/devices/3-1/power/control - - - - auto
w /sys/bus/pci/devices/0000:0e:00.0/power/control - - - - auto

I wrote a shell script to help me do it called http://s.natalian.org/2015-07-08/rewrite.sh:

cleanup() {
	echo $1 | tr -d "';"
}
while read _ arg _ dev
do
	echo w $(cleanup $dev) - - - - $(cleanup $arg)
done < tunables.txt

Which I move into the right place like so:

x220:~/tmp/powertop$ bash rewrite.sh > /tmp/power-savings.conf
x220:~/tmp/powertop$ sudo mv /tmp/power-savings.conf /etc/tmpfiles.d/power-savings.conf

For ethtool and iw have a look at Vodik’s /etc/rules.d/50-network-powersave.rules.