On Mon, Apr 26, 2021 at 11:25 AM Vitaly Zaitsev via devel
On 25.04.2021 20:39, Artem Tim wrote:
> Please provide full PREEMPT mode by default in 5.12 kernel for desktop variants.
With 5.12 it is possible for user to change it without efforts if they need this.
+1 for this. Significantly reduces X11 input lag in full-screen games.
From a kernel standpoint, I do not think turning on CONFIG_PREEMPT is
desired. That sets the *default* to PREEMPT, and changes the current
situation. I plan to keep CONFIG_PREEMPT_VOLUNTARY as the default. The
code introduced is odd, in that you can choose other options (none,
voluntary, full) based on that starting point, but it doesn't allow
you to default to anything else and keep CONFIG_PREEMPT_DYNAMIC on to
choose more preemption than the default. I will see if I can hack
something together and get it upstream that would allow us to keep the
voluntary default and move to preempt with the command line. Moving
forward, if something like that is not accepted, this might be a valid
change for F35, but I don't see it reasonable to change preemption in
stable releases (and the F34 ship has sailed). Even if I do get such
a patch upstream, the default would remain voluntary, and the Desktop
SIG could add a preempt= command line by default for F35+.