We are having difficoulties verifying the RT capabilities of our jetson agx xavier using the PREEMPT_RT patch and the manual from here: https://docs.nvidia.com/jetson/archives/r35.4.1/DeveloperGuide/text/SD/Kernel/KernelCustomization.html
We ran the system once without the PREEMPT_RT patch, booted it up, opened a terminal while in the Ubuntu config still, installed and ran cyclictest using this command:
cyclictest --loops=1000000 --interval=100 --histogram=200 --quiet --policy=fifo --priority=99 > nonRT.txt
We then ran this exact test again using a PREEMPT_RT patched variant of the kernel. uname -a correctly shows the “PREEMPT RT” part. Here are the results compared with each other in a histogram:
As you can see there is no significant difference in latencies which is unexpected since this is a major metric PREEMPT_RT is trying to influence.
Have any of you ran a comparison test like this one? If so what where your results and if they differ from ours: How did you set up the system exactly to get to these better results?