PREEMPT_RT no longer needed in Ubuntu?

I read somewhere that rt PREEMPT_RT kernel build was no longer needed in Ubuntu 23.10/24.04. Is this true? If so how do you access the real time features?

It may not be not needed by Ubuntu, but its certainly needed by LinuxCNC...

Where did you read this ?

"I read somewhere that xxxx" often comes up but rarely is there a source.

PCW wrote:

It may not be not needed by Ubuntu, but its certainly needed by LinuxCNC...

I suspect that they use PREEMPT_DYNAMIC which is definitely not hard real time  PREEMPT_RT

I'm using ubuntu 22.04.4 with the initrd.img-5.15.0-1061-realtime kernel (PREEMPT_RT)
and a Mesa 6i25 pci card.

I get very good jitter so I'll stick with that for now.
I'm running a RIP install of 2.9.0~pre and want to upgrade to 2.9.2 but don't want to loose the edits I've done in the RIP directory.
Any suggestions?

Copy the configs directory to a USB stick, if there are no special components made by you in use, that is all you need.
Ubuntu does not use RT kernels anymore (no idea why), but you can safely use Debian RT kernels in Ubuntu, i know it worked for sure with 6.1 i think.
Edit:
got reminded below by PhillC about why Ubuntu has not RT kernel, they do but it is behind a paywall!

I cloned what I though was 2.9.2 but VERSION says 2.10.0-pre0. It works but should I go back to 2.9.2 which is supposed to be stable. How do I get that version? Is there a branch name for it?

Probably should say 2.9 instead of Master somewhere.
Sorry for the vague reply but was long ago.

ubuntu.com/real-time
 

Yup, but behind a paywall.