almost 20 years ago when I took a Red Hat Kernel internals class (at Redhat) they basically told us to use CentOS if we wanted to experiment with RHEL. (We were preparing for a transition from the HPUX/Solaris machines.). But it worked, some of our architects did that and we could get the scheduler behaving similar to HPUX. I left that company, but I'm pretty sure they did switch and RedHat got a big contract out of it.

We've come a long way.