[Bug] Irregular frequency of rate_ctrl when px4io driver is running

[Igor-Misic]

Describe the bug

I've notice irregular calls in wq:rate_ctrl when px4io drive is running.
For example, control_allocation is expect to run 2.5 [ms] loop but for every 1 [s] it can be seen that is not case.

Here is plot where it can be seen that oscillations are more than double with 1 Hz frequency .
In the first part px4io is running, while in the second part I stopped px4io with stop command and there are not spikes anymore.

I've used control_allocation, but it is the same behavior for all loops that use wq:rate_ctrl.

To Reproduce

Use this code to reproduce:
https://github.com/PX4/PX4-Autopilot/tree/test-rate_ctrl_performance

Software Version

v1.14.4 and main

Flight controller

fmu-v5x

[dakejahl]

Which hardware? I just tested on pixhawk 5x and cube orange and don't see the issue. Do you need to be armed or have anything else plugged in?

[Igor-Misic]

@dakejahl thanks for trying to reproduce and interesting observation. I used a Pixhawk fmu-v5x, only connected device is RC at PX4IO with the SBUS protocol.

I also test with fmu-v6x and can't reproduce. It could be related only to STM32F7 boards.

Edit: I've tested when vehicle is armed