On 2018.11.04 08:31 Rafael J. Wysocki wrote: > v2 -> v3: > * Simplify the pattern detection code and make it return a value > lower than the time to the closest timer if the majority of recent > idle intervals are below it regardless of their variance (that should > cause it to be slightly more aggressive). > * Do not count wakeups from state 0 due to the time limit in poll_idle() > as non-timer. > > Note: I will be mostly offline tomorrow, so this goes slightly early. > I have tested it only very lightly, but it is not so much different from > the previous one. > > It requires the same additional patches to apply as the previous one too.
Even though this v3 has now been superseded by v4, I completed some test work in progress for v3 anyhow. The main reason to complete the work, and write up, was because, and for my own interest as much as anything, I wanted to specifically test for the influence of running trace on the system under test. Reference: https://marc.info/?l=linux-kernel&m=154145580925439&w=2 The Phoronix dbench test was run under the option to run all the tests, instead of just one number of clients. This was done with a reference/baseline kernel of 4.20-rc1, and also with this TEO version 3 patch. The tests were also repeated with trace enabled for 5000 seconds. Idle information and processor package power were sampled once per minute in all test runs. The results are: http://fast.smythies.com/linux-pm/k420/k420-dbench-teo3.htm http://fast.smythies.com/linux-pm/k420/histo_compare.htm Conclusion: trace has negligible effect, until the system gets severely overloaded. There are some odd long idle durations with TEOv3 for idle states 1, 2, and 3 that I'll watch for with v4 testing. Other information: Processor: Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz The kernels were 1000 Hz. Idle latency/residency info: STATE: state0 DESC: CPUIDLE CORE POLL IDLE NAME: POLL LATENCY: 0 RESIDENCY: 0 STATE: state1 DESC: MWAIT 0x00 NAME: C1 LATENCY: 2 RESIDENCY: 2 STATE: state2 DESC: MWAIT 0x01 NAME: C1E LATENCY: 10 RESIDENCY: 20 STATE: state3 DESC: MWAIT 0x10 NAME: C3 LATENCY: 80 RESIDENCY: 211 STATE: state4 DESC: MWAIT 0x20 NAME: C6 LATENCY: 104 RESIDENCY: 345 ... Doug
