On Tue, Jun 30, 2020 at 04:25:23PM +0100, Ankur Sinha wrote: > On Mon, Jun 29, 2020 15:01:24 -0600, Chris Murphy wrote: > > https://bugzilla.redhat.com/show_bug.cgi?id=1851783 > > > > The main argument is that for typical and varied workloads in Fedora, > > mostly on consumer hardware, we should use mq-deadline scheduler > > rather than either none or bfq. > > > > It may be true most folks with NVMe won't see anything bad with none, > > but those who have heavier IO workloads are likely to be better off > > with mq-deadline. > > > > Further details are in the bug, but let's discuss it on list. Thanks! > > There was this thread about our systems hanging, and the workaround was > to revert to mq-deadline from bfq: > > https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx/thread/MJJFT5AOYUFZ3SO2EDVLJSDAZMZI4HAP/#DA7RCQFIAD4Z3Q7HQBW2ELPTLPYDKJMT To clarify: you could reliably reproduce the issue when building steps in mock. Did you verify that it is reliably fixed simply by switching bfq→mq-deadline? Zbyszek > There are a few threads on AskFedora about systems hanging. They're not > the easiest to debug but we did suggest people try switching to > mq-deadline to see if it helps: > > https://ask.fedoraproject.org/t/whole-os-freezes-watching-a-video-with-mpv/6770/10 > > I don't know enough about this to say if it's a bug and if it has been > fixed. There's a lot of noise in those bug reports. For heisenbugs, the fact that something was an issue and after a flurry of half-random changes to the system isn't, does not allow us conclude _anything_. We need somebody who understands what they are doing to isolate the issue. In particular, if this is a kernel hang, than we need a proper traceback from the kernel, and not just assume it's the scheduler. (In particular, if this is a race condition, changing the scheduler could be just making the condition less likely because the system is slower or faster or just schedules processes in a different order, without the scheduler being relevant to the bug). Zbyszek _______________________________________________ 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
