It's good, but ... there's "fully preemptable" and there's "fully preemptable". QNX is one of those, RT_PREEMPT kernels are the other.

I just remembered that I've been running my desktop machine with `preempt=full` for a while now. I wonder why it's not the default for consumer distros yet.

RT_PREEMT has nothing to do with "real" realtime. You never know WHEN the preemtion is gonna happen. Might be in 20ms, might be in 200.