Articles

Reducing desktop power usage while idle

In Gnome, Linux desktop, open source on July 14, 2014 by oli4444

While remotely monitoring my desktop session with powertop while it was idle (screensaver active) I noticed that a few processes cause a lot of activity, and keeping the CPU from going into the PC7 state (the complete cpu package deepest sleep state). Most notably firefox and it’s plugin-container cause frequent wakeups.

I wrote a short script that listens on dbus for screensaver ActiveChanged messages, and either sends a STOP or a CONT signal to firefox and the plugin-container. This script makes my desktop go from 20W to 19W of power when I am not using it.


import subprocess
import datetime

import dbus, gobject
from dbus.mainloop.glib import DBusGMainLoop

stoplist = ['firefox', 'plugin-container', 'steam']
def msg2_cb(msg):
	dt = datetime.datetime.now()
	if (msg):
		for name in stoplist:
			subprocess.call(["killall", "-STOP", name])
	else:
		for name in stoplist:
			subprocess.call(["killall", "-CONT", name])

if __name__ == '__main__':
	DBusGMainLoop(set_as_default=True)
	bus = dbus.SessionBus()
	bus.add_signal_receiver(msg2_cb, 'ActiveChanged', None, None, '/org/gnome/ScreenSaver')
	mainloop = gobject.MainLoop ()
	mainloop.run ()

The obvious caveat is that any downloads by firefox are also stopped if the screensaver becomes active.

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2 Responses to “Reducing desktop power usage while idle”

  1. My Python is rusty but where msg2_cb() get its parameter? From what I understand it’s always going to stop the processes.

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