Zephyr vs. RIOT comparison

[luizvilla]

Hello everyone,

I'm Luiz Villa, a researcher at the University of Toulouse. I'm working with software defined power converters and my team is looking into using an RTOS to manage real-time micro-controllers.
We ran a benchmark between Zephyr and RIOT OS that we would like to share with you.
Spoiler: Zephyr performed poorly.
Here's the summary:

Our test code is available at https://gitlab.laas.fr/owntech/zephyr/-/tree/test_adc_g4

Our target : Nucleo-G474RE

Our main conclusions:

• Zephyr has an overhead of almost 27us compared with 10us from RIOT
• Zephyr consumes 34% of CPU cycles compared with 14% from RIOT
• Zephyr has a period of 12us when we flood the shell compared with 1us from RIOT
• Zephyr has a minimum thread period with an active shell of 38us compared with 40us from RIOT

Our questions for the community:

• Does anyone has the same issues?
• Have you managed to bring the execution time of Zephyr below this threshold?
• Are we missing something on our code?

[nashif]

discussion happening here: #32875