Am 11.02.21 um 15:28 schrieb Peter Robinson:
On Thu, Feb 11, 2021 at 1:03 PM Ondrej Mosnacek omosnace@redhat.com wrote:
On Thu, Feb 11, 2021 at 10:14 AM Viktor Ashirov vashirov@redhat.com wrote:
On Wed, Feb 3, 2021 at 5:54 PM Michael Catanzaro mcatanzaro@gnome.org wrote:
[…]
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:
[…] 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.
FWIW, I wonder if some changes that were merged for mainline this week might be related:
https://git.kernel.org/torvalds/c/291009f656e8eaebbdfd3a8d99f6b190a9ce9deb https://git.kernel.org/torvalds/c/d11a1d08a082a7dc0ada423d2b2e26e9b6f2525c https://git.kernel.org/torvalds/c/3c55e94c0adea4a5389c4b80f6ae9927dd6a4501
But I'm not entirely sure what CPUs are affected by d11a1d08a082
HTH, CU, thl