After some time connected to a docking station, the computer would randomly about 4 times a minute experience extrema lag spikes, with rendering and input devices freezing or stuttering for a few seconds. Spikes vary from lasting upwards of 5 seconds to only a few milliseconds and behaviors have been observed to be worse while running heavy applications.
Debugging
CPU usage seems to be moderate with slight spikes in conjunction with the lag spikes.
Several short lives processes running /bin/sh -c echo 13b1 0bdc > /sys/bus/usb/drivers/brcmfmac/new_id seems to coincide with the lag-spikes
These processes are child processes of systemd-dbus
Inspecting the systemd-dbus debug log (/usr/lib/systemd/systemd-udevd -D) we can confirm that these executions are triggered by the /usr/lib/udev/rules.d/30-linksys-ae1200.rules rule.
Checking the kernel event log (udevadm monitor) we can see that this rules is triggered intermittently by the creation of virtual networks /devices/virtual/net/veth3...
Names of these networks seems to correspond with docker network devices, they can be listed with systemctl list-units | grep sys-devices-virtual-net-veth
Stopping all running docker containers and deleting their networks stops the kernel event activity and also remedies the lag spikes
Upstream
No upstream project seems to have any issues logged for this problem.
TODO
[ ] 1. Investigate if podman is effected
[ ] 2. Create reproducible example
[ ] 3. Report to upstream
[ ] 4. Disable or modify the /usr/lib/udev/rules.d/30-linksys-ae1200.rules rule.
After some time connected to a docking station, the computer would randomly about 4 times a minute experience extrema lag spikes, with rendering and input devices freezing or stuttering for a few seconds. Spikes vary from lasting upwards of 5 seconds to only a few milliseconds and behaviors have been observed to be worse while running heavy applications.
Debugging
/bin/sh -c echo 13b1 0bdc > /sys/bus/usb/drivers/brcmfmac/new_id
seems to coincide with the lag-spikes/usr/lib/systemd/systemd-udevd -D
) we can confirm that these executions are triggered by the/usr/lib/udev/rules.d/30-linksys-ae1200.rules
rule.udevadm monitor
) we can see that this rules is triggered intermittently by the creation of virtual networks/devices/virtual/net/veth3...
systemctl list-units | grep sys-devices-virtual-net-veth
Upstream
No upstream project seems to have any issues logged for this problem.
TODO
/usr/lib/udev/rules.d/30-linksys-ae1200.rules
rule.