[PlanetCCRMA] preempt=full in 5.16.0 (was: Akmod for the realtime kernel)

[Fernando Lopez-Lezcano]

On 1/10/22 3:06 PM, Fernando Lopez-Lezcano wrote:
...
> ==== System A: kernel 5.14.8-200.1.motu.fc34.ccrma (preempt=full)

I did a local build for fc34 of the latest Koji 5.16.0 Fedora source 
package and installed it in my "System B". At least in that source 
package CONFIG_PREEMPT_DYNAMIC is set to "y" (yay!, cross fingers it 
stays that way!) and I can switch to preempt=full when booting without 
any further tweaks.

The kernel no longer prints the status when booting, but "cat 
/sys/kernel/debug/check/preempt" confirms the system is in preempt=full 
state.

The latency numbers I see on my first test and reported by cyclictest 
are not quite as good as "System A" (running 5.14.8), but they are good.

-- Fernando

PS: Anyone knows how to convince pipewire to let go of an audio 
interface? That is, not use it anymore? I'm trying the Motu driver and I 
would like to remove the snd_usb_audio kernel driver to reload the motu 
driver - long story of why, and it is not easy as the driver is in use 
by pipewire...