Long execution time rcl_publish function

[danielallstar]

Long response times rcl_publish

• Hardware description:
  STM32H743ZI
• RTOS:
  Zephyr

Steps to reproduce the issue / behaviour

When running the rcl_publish() micro-ROS function using the best-effort publisher I notice that the function alone takes about 2ms before it completes the function call. My expectation was that this time would be lower.

Expected behavior

When looking at older questions I noticed that the expected time for a rcl_publish function should be around 40us. i do however not see any options to achieve this timing.
https://github.com/micro-ROS/micro_ros_arduino/issues/20#issuecomment-723097131

Therefore, I wondered what I have to do in order to get better function completion times.

Thanks and kind regards,

Daniël