Re: Ars claims: Fedora 32 is sluggish

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, Feb 11, 2021 at 1:03 PM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote:
>
> On Thu, Feb 11, 2021 at 10:14 AM Viktor Ashirov <vashirov@xxxxxxxxxx> wrote:
> > On Wed, Feb 3, 2021 at 5:54 PM Michael Catanzaro <mcatanzaro@xxxxxxxxx> wrote:
> >>
> >> Hi,
> >>
> >> Has anybody investigated Jim Salter's claims that Fedora 32 is slow to
> >> launch applications? Recent article:
> >>
> >> https://arstechnica.com/gadgets/2021/02/ubuntu-core-20-adds-secure-boot-with-hardware-backed-encryption/
> >>
> >> "in my experience, Fedora 32 is noticeably, demonstrably more sluggish
> >> to launch applications than Ubuntu is in general."
> >>
> >> Original article:
> >>
> >> https://arstechnica.com/gadgets/2020/05/linux-distro-review-fedora-workstation-32/
> >>
> >> Would be good to know, for starters, whether this difference is real
> >> and measurable.
> >
> > This was bugging me for a while. I also noticed that Fedora 32 is a bit slower than it used to be. Compilation time of a project that I'm working on went from ~35-36 seconds to ~47-48. At first I thought that it's just another round of CPU vulnerabilities mitigations that introduced a performance drop. But after some digging I found that the default CPU governor was switched from 'ondemand' to 'schedutil' in Fedora kernel 5.9.7:
> > https://src.fedoraproject.org/rpms/kernel/c/73c86ebaee23df8310b903c1dab2176d443f5a3a?branch=rawhide
> > (see configs/fedora/generic/CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL)
> >
> > I switched it back using cpupower from kernel-tools:
> > $ sudo cpupower frequency-set --governor ondemand
> >
> > And confirmed that my compilation time went back to the previous ~35 seconds.
> > In the end I switched the governor to 'performance' and shaved another 5 seconds. And gnome-shell no longer feels sluggish, switching tabs in the browser is also instant.
> > To make the change permanent I used settings in /etc/sysconfig/cpupower and enabled cpupower service:
> > $ sudo systemctl enable --now cpupower.service
> >
> > The change of the default CPU governor looks pretty significant to me, but I couldn't find any discussions about it.
>
> CCing the Fedora kernel list and Justin. At the ARK tree level, the
> change was introduced in this commit, with no explanation:
> https://gitlab.com/cki-project/kernel-ark/commit/9d69ad49ab90db607e25a99eacbf31dc9e513dfa
>
> Justin, do you remember the reason for the change? Can/should it be reverted?

It was upstream changes, the Intel maintainer changed it in [1] if
X86_INTEL_PSTATE state was selected in late March which would make
sense in the timg, and also changed for arm arches [2] in July.

If that change was made upstream I'm assuming it was assumed that
performance should be equivalent or better than the other option, I
suspect we should engage with upstream as they're probably interested
in the issues.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a00ec3874e7d3
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f259eab3ea0e7
_______________________________________________
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 on the list, report it: https://pagure.io/fedora-infrastructure




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Fedora Announce]     [Fedora Users]     [Fedora Kernel]     [Fedora Testing]     [Fedora Formulas]     [Fedora PHP Devel]     [Kernel Development]     [Fedora Legacy]     [Fedora Maintainers]     [Fedora Desktop]     [PAM]     [Red Hat Development]     [Gimp]     [Yosemite News]

  Powered by Linux