On 10/14/25 12:55, Sergey Senozhatsky wrote:
On (25/10/14 11:25), Christian Loehle wrote:
On 10/14/25 11:23, Sergey Senozhatsky wrote:
On (25/10/14 10:50), Christian Loehle wrote:
Upstream fixup fa3fa55de0d ("cpuidle: governors: menu: Avoid using invalid recent intervals data") doesn't address the problems we are observing. Revert seems to be bringing performance metrics back to pre-regression levels.
Any details would be much appreciated. How do the idle state usages differ with and without "cpuidle: menu: Avoid discarding useful information"? What do the idle states look like in your platform?
Sure, I can run tests. How do I get the numbers/stats that you are asking for?
Ideally just dump cat /sys/devices/system/cpu/cpu*/cpuidle/state*/* before and after the test.
OK, got some data for you. The terminology being used here is as follows:
6.1-base is 6.1 stable with a9edb700846 "cpuidle: menu: Avoid discarding useful information"
6.1-base-fixup is 6.1 stable with a9edb700846 and fa3fa55de0d6 "cpuidle: governors: menu: Avoid using invalid recent intervals data" cherry-pick
6.1-revert is 6.1 stable with a9edb700846 reverted (and no fixup commit, obviously)
Just to show the scale of regression, results of some of the benchmarks:
6.1-base: 84.5 6.1-base-fixup: 76.5 6.1-revert: 59.5
(lower is better, 6.1-revert has the same results as previous stable kernels).
This immediately threw me off. The fixup was written for a specific system which had completely broken cpuidle. It shouldn't affect any sane system significantly. I double checked the numbers and your system looks fine, in fact none of the tests had any rejected cpuidle occurrences. So functionally base and base-fixup are identical for you. The cpuidle numbers are also reasonably 'in the noise', so just for the future some stats would be helpful on those scores.
I can see a huge difference between base and revert in terms of cpuidle, so that's enough for me to take a look, I'll do that now. (6.1-revert has more C3_ACPI in favor of C1_ACPI.)
(Also I can't send this email without at least recommending teo instead of menu for your platform / use-cases, if you deemed it unfit I'd love to know what didn't work for you!)