On Mon, Apr 26, 2021 at 5:12 PM Andrew Lutomirski <l...@mit.edu> wrote: > > On Mon, Apr 26, 2021 at 1:29 PM Justin Forbes <jmfor...@linuxtx.org> wrote: > > > > On Mon, Apr 26, 2021 at 11:25 AM Vitaly Zaitsev via devel > > <devel@lists.fedoraproject.org> wrote: > > > > > > 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. > > I'm curious: why do you prefer voluntary as the default instead of full > preempt?
It has always been a nice balance for Fedora where we do have a lot of desktop users, but also a lot of server users. And it has been well tested as the Fedora default for quite some time, and the default for RHEL as well. I don't specifically dislike the full preempt, but introducing such a change to rebases on release Fedora is a risk I don't think we should take. I might be willing to make such a change for Fedora 35, where we have plenty of time to test on various workloads, but that doesn't help anyone for a good 6 months. I would much rather get the option for users now (I will even put the patch in 5.12 if I know it is headed upstream). > > 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've pinged the right people. I'll try to make this happen. Thanks. If not I can take a look. The code looks good, it is just an unfortunate lack of options for distros who would like to use dynamic without disrupting defaults. Justin _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
