CPU Scaling Governor
Issue: Cpu Scaling Governor
We have seen some issues with the scaling cpu governor on the Raspberry PI interfere with the i2c bus. This sometimes causes the ZYMKEY to be put into a odd state or return failures from operations that get optimized out by the governor.
Workaround Solution We Recommend:
The PI sets the scaling governor to be
ondemand by default. We recommend switching this mode to
performance to get the best out of the ZYMKEY.
Note: Switching to
performancewill use more battery power.
performance for current boot; not persistent on reboot:
- Run as root:
echo performance > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
performance to be persistent on reboot with a systemd service:
- Create a .service file in /etc/systemd/system/. You can name it whatever you wish. We will use
- Write this code to
[Unit] Description=Set scaling governor to performance After=multi-user.target Before=zkbootrtc.service [Service] Type=oneshot ExecStart=/bin/sh -c "echo performance > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor" [Install] WantedBy=multi-user.target
- Enable the service:
sudo systemctl enable cpu-governor
- Start the service:
sudo systemctl start cpu-governor
Verifying the setting
You can use
cat to verify the current setting. It should return
sudo cat /sys/devices/system/cpu/cpufreq/policy0/scaling_governor