On Sat, May 20, 2023 at 3:44 PM Demi Marie Obenour <demiobenour@xxxxxxxxx> wrote: > > I noticed that by default, Qubes OS has voluntary kernel preemption > as opposed to full preemption. I found that enabling full preemption > (preempt=full on kernel command line) makes the system significantly > more responsive under heavy I/O load. In particular, if I build a > kernel in a Qubes OS VM, it significantly degrades responsiveness > without preempt=full. With preempt=full, the system remains > responsive. The storage stack used is LVM thin provisioning on LUKS, > and I have observed significant CPU usage in dom0 kernel threads with > names that indicate they are related to dm-thin and dm-crypt. > For workstation, preempt=full does likely make sense, and I have been running it for a while. For server, maybe not so much. That is the joy of dynamic preempt. You can boot with preempt=full and run that way if you like. There is an open issue for the workstation WG to look at making preempt=full the default there at some point. > The kernel config used by the Qubes kernel package I use (6.1.28) is > based on Fedora 37’s config, and Marek Marczykowski-Górecki (CCd) > indicated that the same arguments apply to Fedora. Therefore, I am > asking if Fedora should use full kernel preemption by default. I would still say no, as we do have dynamic, and you can set it to whatever you like. Justin > Sincerely, > Demi Marie Obenour (she/her/hers)_______________________________________________ _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
