Comment by jovial_cavalier
Comment by jovial_cavalier 10 months ago
I'm not claiming that there's no difference - just that with the limited tests I ran, preempt_rt is not nearly as good as xenomai.
Comment by jovial_cavalier 10 months ago
I'm not claiming that there's no difference - just that with the limited tests I ran, preempt_rt is not nearly as good as xenomai.
That is not too surprising.
Linux is still Linux, and having Linux as a whole be preemptable by a separate RTOS kernel is always going to perform better in the realtime front, relative to trusting Linux to satisfy realtime for the user tasks it runs.
Incidentally, seL4[0] can pull off that trick, and do it even better: It can support mixed criticality (MCS), where hard realtime is guaranteed by proofs despite less important tasks, such as a Linux kernel under VMM, running on the same system.
0. https://sel4.systems/About/seL4-whitepaper.pdf