[osamagirl69]

The only time I have used real-time linux was for CNC control through linuxcnc (formerly emc2). https://linuxcnc.org/

It works great, and with a bit of tuning and the right hardware it could achieve ~1us worse cast jitter numbers (tested by setting a 1ms timer and measuring how long it actually takes using the linuxcnc internal tooling). Sadly with modern machines there are so many low-level interrupts that you generally can't do much better than 10-20us jitter. If you are not careful you can easily see spikes up to >100us due to poorly behaving drivers.

[gorbypark]

Came here to say basically the same thing. Linux CNC on an old PC with a parallel port can do some amazing things!