Speaker
Description
With the PREEMPT_RT configuration being merged for the 6.12 release a milestone of a twenty years lasting journey was reached: Linux officially became an RTOS! During that time many technical issues have been resolved and many features have been added that made Linux even better even for non real-time users. A specific challenge which had to be tackled was testing and proving the real-time behavior. While for classical RTOSes traditionally a path analysis was carried out, this is close to impossible for a modern operating system such as Linux - not just because of the complexity of the software: Modern processors do come with a lot of performance with the price of being non-deterministic due to several levels of caches, speculation engines and other techniques. As a result the real-time behavior of modern systems has to be evaluated. This is why the OSADL QA Farm was born, doing comparable measurements on a huge variety of systems collecting long-term data to prove stability in the field. But even after 20 years of operation work is not done yet. Linux is evolving rapidly and the test scenarios (also for real-time) have to adopt. Apart from that Open Source RTOSes are also approaching small processors. This is why the OSADL QA Farm was recently extended with Zephyr tests.
This presentation gives an overview on best practices for evaluating the real-time behavior of Linux (and other) systems, sharing the experience from the OSADL QA Farm. It also wants to serve as a basis for discussion on how measurements shall be carried out in future and how data can be efficiently shared.