FWIW, I have taken to CONFIG_PREEMPT=y in my hacking kernels because it
exposed on my clunky test machines bugs that were otherwise reproduced only
on big honking machines with lots of parallelism. I haven't experienced a
bug that wasn't there at all with CONFIG_PREEMPT=n, only ones that were
hard to reproduce in hacker's conditions but more likely in production load
conditions. So, out of sight, out of mind, sure. But out of sight,
lurking to bite you in the ass later when you really aren't in the mood,
also damn likely.
Roland