Messages in this thread | | | From | Lukasz Luba <> | Subject | [RFC PATCH v3 0/5] Introduce Cpufreq Active Stats | Date | Wed, 6 Apr 2022 23:08:04 +0100 |
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Hi all,
This is the 3rd version of patch set which tries to address issues which are due to missing proper information about CPU performance in time.
The issue description: 1. "Cpufreq statistics cover the time when CPUs are in idle states, so they are not suitable for certain purposes, like thermal control." Rafael [2] 2. Thermal governor Intelligent Power Allocation (IPA) has to estimate power, for the last period, e.g. 100ms, for each CPU in the Cluster, to grant new power and set max possible frequency. Currently in some cases it gets big error, when the frequency of CPU changed in the middle. It is due to the fact that IPA reads the current frequency for the CPU, not aware of all other frequencies which were actively (not in idle) used in the last 100ms.
This code focuses on tracking the events of idle entry/exit for each CPU and combine them with the frequency tracked statistics inside internal statistics arrays (per-CPU). In the old cpufreq stats we have one shared statistics array for the policy (all CPUs) and not take into account periods when each CPU was in idle.
Sometimes the IPA error between old estimation signal and reality is quite big (>50%).
changelog: v3: - moved the core implementation into the cpufreq and not creating a new framework (as sugested by Rafael) - updated all function names and APIs v2 [1]
Regards, Lukasz Luba
[1] https://lore.kernel.org/all/20210706131828.22309-1-lukasz.luba@arm.com/ [2] https://lore.kernel.org/all/CAJZ5v0gzpfT__EyrVuZSr32ms7-YJZw7qEok0WZECv1iDRRvWA@mail.gmail.com/
Lukasz Luba (5): cpufreq: stats: Introduce Cpufreq Active Stats cpuidle: Add Cpufreq Active Stats calls tracking idle entry/exit thermal: Add interface to cooling devices to handle governor change thermal: power allocator: Prepare power actors and calm down when not used thermal: cpufreq_cooling: Improve power estimation using Cpufreq Active Stats
MAINTAINERS | 2 +- drivers/cpufreq/cpufreq_stats.c | 872 ++++++++++++++++++++++++++ drivers/cpuidle/cpuidle.c | 5 + drivers/thermal/cpufreq_cooling.c | 131 ++++ drivers/thermal/gov_power_allocator.c | 71 +++ include/linux/cpufreq_stats.h | 131 ++++ include/linux/thermal.h | 1 + 7 files changed, 1212 insertions(+), 1 deletion(-) create mode 100644 include/linux/cpufreq_stats.h
-- 2.17.1
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