performy

Small Linux daemon for systemd. It watches charger state and switches both GNOME power profiles and CPU frequency policy.

Created in the ArmaniOS era, adapted for GNOME and modern distributions.

On battery:

1. powerprofilesctl set power-saver
2. wait GNOME_SETTLE_SECONDS so GNOME/power-profiles-daemon applies the mode first
3. cpupower -c all frequency-set -g powersave
4. cpupower -c all frequency-set -d 300MHz -u 700MHz
5. while on battery, adapt the upper cap from 700 MHz upward only after sustained load

On AC:

1. restore CPU min/max limits from sysfs
2. cpupower -c all frequency-set -g performance
3. powerprofilesctl set performance

Requirements

• Linux with /sys/class/power_supply
• cpupower
• powerprofilesctl from power-profiles-daemon
• root service permissions, because cpupower changes CPU policy

Install

Do not run multiple power managers at the same time. Disable tools such as TLP, auto-cpufreq, tuned, or distro-specific power daemons if they overwrite powerprofilesctl, governor, or cpufreq limits.

Fedora

Install runtime dependencies:

sudo dnf install python3 kernel-tools power-profiles-daemon
sudo systemctl enable --now power-profiles-daemon.service

Install performy:

sudo ./install.sh
sudo systemctl status performy.service

Arch Linux

Install runtime dependencies:

sudo pacman -S python cpupower power-profiles-daemon
sudo systemctl enable --now power-profiles-daemon.service

Install performy:

sudo ./install.sh
sudo systemctl status performy.service

Ubuntu

Install runtime dependencies:

sudo apt update
sudo apt install python3 power-profiles-daemon linux-tools-common linux-tools-generic
sudo systemctl enable --now power-profiles-daemon.service

If cpupower is still missing, install the cpupower package available for your Ubuntu release:

sudo apt install linux-cpupower

Install performy:

sudo ./install.sh
sudo systemctl status performy.service

Debian

Install runtime dependencies:

sudo apt update
sudo apt install python3 power-profiles-daemon linux-cpupower
sudo systemctl enable --now power-profiles-daemon.service

Install performy:

sudo ./install.sh
sudo systemctl status performy.service

NixOS

Import the provided module from /etc/nixos/configuration.nix:

{
  imports = [
    /home/csoftware/performy/nixos/performy.nix
  ];
}

Apply it:

sudo nixos-rebuild switch
sudo systemctl restart performy.service
journalctl -u performy.service -f

The NixOS module installs performy-daemon system-wide, enables power-profiles-daemon, creates /etc/performy.conf from performy.conf.example, and starts the root systemd service.

Post-install checks

Edit /etc/performy.conf if your CPU does not support the default 650-700 MHz range.

Useful commands:

sudo performy-daemon --once --dry-run
sudo systemctl status performy.service
journalctl -u performy.service -f

Configuration

Copy or edit performy.conf.example. The defaults implement:

• battery: GNOME power-saver, governor powersave, idle floor 300 MHz, normal band 650-700 MHz, adaptive boost to average CPU frequency under sustained per-core load
• AC: hardware min/max limits, governor performance, GNOME performance

Set ENABLE_GNOME=false or ENABLE_CPUPOWER=false if you need only one side of the switching.

Keep GNOME_SETTLE_SECONDS above zero if your hardware does not lower CPU frequency until GNOME switches to power-saver.

If cpupower -d/-u fails with Trying to set an invalid policy?, keep:

FREQUENCY_LIMIT_BACKEND=sysfs

The daemon will still use cpupower for governor changes, but will write min/max frequency limits directly to policy*/scaling_min_freq and policy*/scaling_max_freq.

Adaptive Battery Mode

Adaptive mode is enabled by default with BATTERY_ADAPTIVE=true.

• BATTERY_IDLE_MIN_FREQ=300MHz lets the CPU drop lower while idle. If the CPU reports a higher hardware minimum, performy clamps to that value instead of sending an invalid cpupower policy.
• BATTERY_MIN_FREQ=650MHz and BATTERY_MAX_FREQ=700MHz define the normal battery band.
• BATTERY_BOOST_MAX_FREQ=average caps battery boost at the midpoint between hardware min and max frequency.
• BATTERY_BOOST_STEP_FREQ=average jumps to that average cap when boost is needed.
• BATTERY_BOOST_UP_LOAD=60 and BATTERY_BOOST_UP_SAMPLES=1 react to sustained per-core load; one hot core is enough to boost.
• BATTERY_BOOST_DOWN_LOAD=35, BATTERY_BOOST_DOWN_SAMPLES=3, and BATTERY_BOOST_DOWN_HOLD_SECONDS=20 make it drop back conservatively.

Set BATTERY_ADAPTIVE=false to get the old static 650-700 MHz battery behavior.