On 2026.01.20 07:30 Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > If differences between target residency values of adjacent idle states > of a given CPU are relatively large, the corresponding idle state bins > used by the teo governors are large either and the rule by which hits > are distinguished from intercepts is inaccurate. > > Namely, by that rule, a wakeup event is classified as a hit if the > sleep length (the time till the closest timer other than the tick) > and the measured idle duration, adjusted for the entered idle state > exit latency, fall into the same idle state bin. However, if that bin > is large enough, the actual difference between the sleep length and > the measured idle duration may be significant. It may in fact be > significantly greater than the analogous difference for an event where > the sleep length and the measured idle duration fall into different > bins. > > For this reason, amend the rule in question with a check that will > only allow a wakeup event to be counted as a hit if the difference > between the sleep length and the measured idle duration is less than > LATENCY_THRESHOLD_NS (which means that the difference between the > sleep length and the raw measured idle duration is below the sum of > LATENCY_THRESHOLD_NS and 1/2 of the entered idle state exit latency). > Otherwise, the event will be counted as an intercept. > > Signed-off-by: Rafael J. Wysocki > --- > > v1 -> v1.1 > * Drop the change in teo_select() along with the corresponding > part of the changelog (after receiving testing feedback from > Christian) With this updated patch I have not observed any difference in testing results or power consumption between kernels without or with the 5 patch set: c66de7fc0157 (HEAD -> rjw-1-1) cpuidle: governors: teo: Adjust the classification of wakeup events 25f70be81668 Revert "cpuidle: governors: teo: Adjust the classification of wakeup events" f0ae302c4635 cpuidle: governors: teo: Refine intercepts-based idle state lookup f5ad355214de cpuidle: governors: teo: Adjust the classification of wakeup events 1c5b66c336ea cpuidle: governors: teo: Refine tick_intercepts vs total events check 36148eea2ec2 cpuidle: governors: teo: Avoid fake intercepts produced by tick 8b1ad7bc8a7f cpuidle: governors: teo: Avoid selecting states with zero-size bins 0f61b1860cc3 (tag: v6.19-rc5, origin/master, origin/HEAD, master) Linux 6.19-rc5 My test system: Processor: Intel(R) Core(TM) i5-10600K CPU @ 4.10GHz, 6 cores 12 CPUs. HWP: Enabled. state0/name:POLL state1/name:C1_ACPI state2/name:C2_ACPI state3/name:C3_ACPI @Christian: I noticed that you like "idle misses" in test results. I have added percent "idle misses" to my test results. An example graph is attached. Legend: rc5 = kernel 6.19-rc5 rjw = kernel 6.19-rc5 + original 5 patch set rjw-1-1 = kernel 6.19-rc5 + current 5 patch set See also my previous email [1] about the original 5 patch set: [1] https://lore.kernel.org/linux-pm/003201dc895f$8cfb2540$a6f16fc0$@telus.net/ ... Doug