Every once in a while I try the stock Arch Linux kernel with my reference low latency audio setup - just to see how it goes against the RT Kernel from the Arch User Repository.
The experiment usually doesn't last for long, but this time it is going a lot better:
I was quite surprised to find out that as of Linux 4.19, the stock Arch kernel handles latencies as low as 2ms just fine - this was clearly not the case one year ago with 4.16.
I didn't run any precise measurement with rt tests, just my empirical benchmark with Guitarix & Jack1 running at 64 samples with 3 periods @ 96KHz with a Focusrite Scarlett 2i2 first gen (on an old Ivy Bridge notebook).
This gives ~2ms in + 2ms out + 2-3 ms AD/DA conversion = 6-7ms round trip latency.
With this config I could run for an hour or so with zero xruns - same as with the RT kernel - sweet!
Adding Ardour and/or Renoise to the mix and I get a few xruns, but this was anyway not better with RT.
I wouldn't be able to tell if those results are due to the Arch kernel patches or just the performance improvements upstream, but if you're cringing at the build times of the RT kernel, and your distro provides a recent kernel like Linux 4.19 or 4.20 this may be worth another shot
