Set powersave/performance governor based on ac/battery status

_watch-cpu-freq.md

This setup switches to "powersave" if the battery is lower than 75% and to "performance" if it is above and charging.

Copy the files to

• /etc/systemd/system/watch-power-cpufreq.service
• /usr/local/bin/watch-power-cpufreq.sh

and then run

sudo systemctl daemon-reload
sudo systemctl start watch-power-cpufreq.service
systemctl enable watch-power-cpufreq.service

Update: I added an installation script. Just do

curl -L https://gist.github.com/nknapp/8b4e10788b65ab9e921ef50e1a3ac60f/raw/install.sh | sudo bash

install.sh

GIST_URL=https://gist.github.com/nknapp/8b4e10788b65ab9e921ef50e1a3ac60f/raw

curl -L -o /usr/local/bin/watch-power-cpufreq.sh $GIST_URL/watch-power-cpufreq.sh
chmod a+x /usr/local/bin/watch-power-cpufreq.sh


systemctl disable watch-power-cpufreq.service || true
systemctl stop watch-power-cpufreq.service || true

curl -L -o /etc/systemd/system/watch-power-cpufreq.service $GIST_URL/watch-power-cpufreq.service

systemctl daemon-reload
systemctl enable watch-power-cpufreq.service
systemctl start watch-power-cpufreq.service

watch-power-cpufreq.service

[Unit]
After=local-fs.target

[Service]
ExecStart=/usr/local/bin/watch-power-cpufreq.sh
Restart=on-failure
RestartSec=30

[Install]
WantedBy=multi-user.target

watch-power-cpufreq.sh

#!/bin/bash

# Set governor to powersave for lower values
CAPACITY_THRESHOLD=75


function setGovernor() {
  GOV=$1
  echo "Switching to governor: $GOV"
  for GOV_FILE in /sys/devices/system/cpu/cpufreq/*/scaling_governor ; do
    echo "${GOV}" > $GOV_FILE
  done
}

while true; do
  BATTERY_STATUS=$( cat /sys/class/power_supply/BAT0/status )
  BATTERY_CAPACITY=$( cat /sys/class/power_supply/BAT0/capacity )
  case "${BATTERY_STATUS}" in 
    "Discharging")
	echo "Battery discharging at ${BATTERY_CAPACITY}%"
        if [ ${BATTERY_CAPACITY} -lt ${CAPACITY_THRESHOLD} ]; then
           setGovernor "powersave"
        else 
           setGovernor "performance"
        fi
    ;;
    *) 
	echo "Battery status: ${BATTERY_STATUS}"
	setGovernor "performance"
    ;;
  esac
  inotifywait /sys/class/power_supply/AC/online /sys/class/power_supply/BAT0/capacity || exit 1
done

Fixed "WantedBy" to "multi-user.target". Added Restart policy