Tools to lower power consumption and device cooling

CPU frequency scaling and battery optimization for Notebook and PC systems

Since the Atlantis release, in December 2021, every new install has power-profile-daemon installed by default.

Why power-profiles-daemon

The power-profiles-daemon project was created to help provide a solution for two separate use cases, for desktops, laptops, and other devices running a “traditional Linux desktop”.

The first one is a “Low Power” mode, that users could toggle themselves, or have the system toggle for them, with the intent to save battery. Mobile devices running iOS and Android have had a similar feature available to end-users and application developers alike.

The second use case was to allow a “Performance” mode on systems where the hardware maker would provide and design such a mode. The idea is that the Linux kernel would provide a way to access this mode which usually only exists as a configuration option in some machines’ “UEFI Setup” screen.

This second use case is the reason why we didn’t implement the “Low Power” mode in UPower, as was originally discussed.

As the daemon would change kernel settings, we would need to run it as root, and make its API available over D-Bus, as has been customary for more than 10 years. We would also design that API to be as easily usable to build graphical interfaces as possible.

Introduction

power-profiles-daemon offers to modify system behaviour based upon user-selected power profiles. There are 3 different power profiles, a “balanced” default mode, a “power-saver” mode, as well as a “performance” mode. The first 2 of those are available on every system. The “performance” mode is only available on select systems and is implemented by different “drivers” based on the system or systems it targets.

In addition to those 2 or 3 modes (depending on the system), “actions” can be hooked up to change the behaviour of a particular device. For example, this can be used to disable the fast charging for some USB devices when in power-saver mode.

GNOME’s Settings and shell both include interfaces to select the current mode, but they are also expected to adjust the behaviour of the desktop depending on the mode, such as turning the screen off after inaction more aggressively when in power-saver mode.

How to use

There are interfaces to switch profiles in the latest versions of KDE and GNOME. Those desktops also include more thorough integration with its low-power mode. Please check the user guides for each of them for details.

power-profiles-daemon also ships with a command-line utility called powerprofilesctl which can be used for scripting, as it allows getting and setting the active profile, listing the available profiles, and launching commands while holding the performance or the power-saver profile.

For example, this will be useful to avoid manual switching profiles while compiling large projects:

powerprofilesctl launch make

If you’re a developer, you might also want to use GLib’s GPowerProfileMonitor through C or one of its bindings, so your application can react to the user requesting a low-power mode.

Debugging

You can now check which mode is in use, and which ones are available by running:

powerprofilesctl get

You can change the selected profile by running (change power-saver for the chosen profile):

powerprofilesctl set power-saver

You can check the current configuration which will be restored on reboot in /var/lib/power-profiles-daemon/state.ini.

Those commands are also available through the D-Bus interface:

gdbus introspect --system --dest net.hadess.PowerProfiles --object-path /net/hadess/PowerProfiles
gdbus call --system --dest net.hadess.PowerProfiles --object-path /net/hadess/PowerProfiles --method org.freedesktop.DBus.Properties.Set 'net.hadess.PowerProfiles' 'ActiveProfile' "<'power-saver'>"

If that doesn’t work, please file an issue, attach the output of:

sudo G_MESSAGES_DEBUG=all /usr/libexec/power-profiles-daemon -r -v

Testing

If you don’t have hardware that can support the performance mode or the degraded mode you can manually run the power-profiles-daemon binary as root with the environment variable POWER_PROFILE_DAEMON_FAKE_DRIVER set to 1. For example:

sudo POWER_PROFILE_DAEMON_FAKE_DRIVER=1 /usr/libexec/power-profiles-daemon -r -v

power-profiles-daemon source text and more info over here.

Thermald

is a Linux daemon used to prevent the overheating of platforms? This daemon monitors temperature and applies compensation using available cooling methods.

By default, it monitors Intel CPU temperature using available CPU digital temperature sensors and maintains CPU temperature under control, before HW takes aggressive correction action. If there is a skin temperature sensor in thermal sysfs, then it tries to keep skin temperature under 45C.

Source: https://wiki.archlinux.org

Code Source:

https://01.org/linux-thermal-daemon/documentation/introduction-thermal-daemon

https://github.com/intel/thermal_daemon

As each update of the thermald-package will overwrite the service file we need to move this to

/etc/systemd/system/

So that it will not stop working after thermald updates.

install needed:

sudo pacman -S --needed thermald

sudo cp /usr/lib/systemd/system/thermald.service /etc/systemd/system/
sudo nano /etc/systemd/system/thermald.service

change the line:

ExecStart=/usr/bin/thermald --systemd --dbus-enable --adaptive

like so:

ExecStart=/usr/bin/thermald --systemd --dbus-enable --adaptive --ignore-cpuid-check

save the file by pressing [Ctrl+Alt+x] and confirm by typing “y”

The last two things to do is enable the systemd service for Thermald to automatic start it on every boot of your system:

sudo systemctl enable thermald

and now please reboot the system to make it start working.

As EndeavourOS is installing power-profiles-daemon per default you will need to mask its service or uninstall it.

sudo systemctl mask power-profiles-daemon

It will need some time to measure and then really control to hold the temperature down, so be patient and wait to see the effect for some time ( may need one or two hours before working for the first time)

Alternative to thermald (auto-cpufreq)

https://github.com/AdnanHodzic/auto-cpufreq

Not available on the official repository, so it needs to be built from AUR:

https://aur.archlinux.org/packages/auto-cpufreq-git/

yay -S auto-cpufreq-git

On how to enable and use this read the documentation on GitHub:

https://github.com/AdnanHodzic/auto-cpufreq#aur-package-archmanjaro-linux

Cpupower

is a set of userspace utilities designed to assist with CPU frequency scaling.

full list of available modules:

sudo ls /usr/lib/modules/$(uname -r)/kernel/drivers/cpufreq/

Load the appropriate module (see Kernel modules for details). Once the appropriate cpufreq driver is loaded, detailed information about the CPU(s) can be displayed by running

sudo cpupower frequency-info

Scaling governors

Governors (see table below) are power schemes for the CPU. Only one may be active at a time. For details, see the kernel documentation in the kernel source.

NOTE: If you want to use this method, make sure you disable CPU-scaling from TLP (as this is enabled by default on EndeavourOS and using both together for the same mechanism will cause failure)

Governor	Description
performance	Run the CPU at the maximum frequency.
powersave	Run the CPU at the minimum frequency.
userspace	Run the CPU at user-specified frequencies.
OnDemand	Scales the frequency dynamically according to the current load. Jumps to the highest frequency and then possibly back off as the idle time increases.
conservative	Scales the frequency dynamically according to the current load. Scales the frequency more gradually than onDemand.
schedutil ………………………..	Scheduler-driven CPU frequency selection [1], [2].

set one for all cores:
(replace governor with e.g. what you want ondemand p.e…)

sudo echo *governor* > /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

see live output:

watch grep \"cpu MHz\" /proc/cpuinfo

making one permanent:

sudo systemctl enable cpupower.service