The kdbuswreck

>Secondly, AFAIR, the current dbus daemon gets penalized by fair kernel scheduling. That issue goes away with kdbus. Lastly I think that it's prety clear that kdbus unlocks a whole new level of performance with code based on memfd that current dbus doesn't use.

yes, I concur here.
The switch to the CFS broke some use cases at the place I was working at that time.

but probably, those use cases where a bit stupid ;)