user/sven/linux.git/kernel/power, branch v5.13.17

PM: EM: Increase energy calculation precision

2021-09-15T08:00:44Z

[ Upstream commit 7fcc17d0cb12938d2b3507973a6f93fc9ed2c7a1 ] The Energy Model (EM) provides useful information about device power in each performance state to other subsystems like: Energy Aware Scheduler (EAS). The energy calculation in EAS does arithmetic operation based on the EM em_cpu_energy(). Current implementation of that function uses em_perf_state::cost as a pre-computed cost coefficient equal to: cost = power * max_frequency / frequency. The 'power' is expressed in milli-Watts (or in abstract scale). There are corner cases when the EAS energy calculation for two Performance Domains (PDs) return the same value. The EAS compares these values to choose smaller one. It might happen that this values are equal due to rounding error. In such scenario, we need better resolution, e.g. 1000 times better. To provide this possibility increase the resolution in the em_perf_state::cost for 64-bit architectures. The cost of increasing resolution on 32-bit is pretty high (64-bit division) and is not justified since there are no new 32bit big.LITTLE EAS systems expected which would benefit from this higher resolution. This patch allows to avoid the rounding to milli-Watt errors, which might occur in EAS energy estimation for each PD. The rounding error is common for small tasks which have small utilization value. There are two places in the code where it makes a difference: 1. In the find_energy_efficient_cpu() where we are searching for best_delta. We might suffer there when two PDs return the same result, like in the example below. Scenario: Low utilized system e.g. ~200 sum_util for PD0 and ~220 for PD1. There are quite a few small tasks ~10-15 util. These tasks would suffer for the rounding error. These utilization values are typical when running games on Android. One of our partners has reported 5..10mA less battery drain when running with increased resolution. Some details: We have two PDs: PD0 (big) and PD1 (little) Let's compare w/o patch set ('old') and w/ patch set ('new') We are comparing energy w/ task and w/o task placed in the PDs a) 'old' w/o patch set, PD0 task_util = 13 cost = 480 sum_util_w/o_task = 215 sum_util_w_task = 228 scale_cpu = 1024 energy_w/o_task = 480 * 215 / 1024 = 100.78 => 100 energy_w_task = 480 * 228 / 1024 = 106.87 => 106 energy_diff = 106 - 100 = 6 (this is equal to 'old' PD1's energy_diff in 'c)') b) 'new' w/ patch set, PD0 task_util = 13 cost = 480 * 1000 = 480000 sum_util_w/o_task = 215 sum_util_w_task = 228 energy_w/o_task = 480000 * 215 / 1024 = 100781 energy_w_task = 480000 * 228 / 1024 = 106875 energy_diff = 106875 - 100781 = 6094 (this is not equal to 'new' PD1's energy_diff in 'd)') c) 'old' w/o patch set, PD1 task_util = 13 cost = 160 sum_util_w/o_task = 283 sum_util_w_task = 293 scale_cpu = 355 energy_w/o_task = 160 * 283 / 355 = 127.55 => 127 energy_w_task = 160 * 296 / 355 = 133.41 => 133 energy_diff = 133 - 127 = 6 (this is equal to 'old' PD0's energy_diff in 'a)') d) 'new' w/ patch set, PD1 task_util = 13 cost = 160 * 1000 = 160000 sum_util_w/o_task = 283 sum_util_w_task = 293 scale_cpu = 355 energy_w/o_task = 160000 * 283 / 355 = 127549 energy_w_task = 160000 * 296 / 355 = 133408 energy_diff = 133408 - 127549 = 5859 (this is not equal to 'new' PD0's energy_diff in 'b)') 2. Difference in the 6% energy margin filter at the end of find_energy_efficient_cpu(). With this patch the margin comparison also has better resolution, so it's possible to have better task placement thanks to that. Fixes: 27871f7a8a341ef ("PM: Introduce an Energy Model management framework") Reported-by: CCJ Yeh Reviewed-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

PM: sleep: fix typos in comments

2021-04-08T17:37:21Z

Change "occured" to "occurred" in kernel/power/autosleep.c. Change "consiting" to "consisting" in kernel/power/snapshot.c. Change "avaiable" to "available" in kernel/power/swap.c. No functionality changed. Signed-off-by: Lu Jialin Signed-off-by: Rafael J. Wysocki

PM: EM: postpone creating the debugfs dir till fs_initcall

2021-03-23T18:53:48Z

The debugfs directory '/sys/kernel/debug/energy_model' is needed before the Energy Model registration can happen. With the recent change in debugfs subsystem it's not allowed to create this directory at early stage (core_initcall). Thus creating this directory would fail. Postpone the creation of the EM debug dir to later stage: fs_initcall. It should be safe since all clients: CPUFreq drivers, Devfreq drivers will be initialized in later stages. The custom debug log below prints the time of creation the EM debug dir at fs_initcall and successful registration of EMs at later stages. [ 1.505717] energy_model: creating rootdir [ 3.698307] cpu cpu0: EM: created perf domain [ 3.709022] cpu cpu1: EM: created perf domain Fixes: 56348560d495 ("debugfs: do not attempt to create a new file before the filesystem is initalized") Reported-by: Ionela Voinescu Signed-off-by: Lukasz Luba Reviewed-by: Greg Kroah-Hartman Signed-off-by: Rafael J. Wysocki

Merge branches 'powercap' and 'pm-misc'

2021-02-15T17:50:01Z

* powercap: powercap: intel_rapl: Use topology interface in rapl_init_domains() powercap: intel_rapl: Use topology interface in rapl_add_package() powercap/intel_rapl: add support for AlderLake Mobile powercap/drivers/dtpm: Fix size of object being allocated powercap/drivers/dtpm: Fix an IS_ERR() vs NULL check powercap/drivers/dtpm: Fix some missing unlock bugs powercap/drivers/dtpm: Fix a double shift bug powercap/drivers/dtpm: Fix __udivdi3 and __aeabi_uldivmod unresolved symbols powercap/drivers/dtpm: Add CPU energy model based support powercap/drivers/dtpm: Add API for dynamic thermal power management Documentation/powercap/dtpm: Add documentation for dtpm units: Add Watt units * pm-misc: PM: Kconfig: remove unneeded "default n" options PM: EM: update Kconfig description and drop "default n" option

PM: sleep: Constify static struct attribute_group

2021-02-12T15:46:59Z

The only usage of suspend_attr_group is to put its address in an array of pointers to const attribute_group structs. Make it const to allow the compiler to put it into read-only memory. Signed-off-by: Rikard Falkeborn Signed-off-by: Rafael J. Wysocki

PM: Kconfig: remove unneeded "default n" options

2021-02-12T15:43:23Z

Remove "default n" options. If the "default" line is removed, it defaults to 'n'. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: EM: update Kconfig description and drop "default n" option

2021-02-12T15:43:23Z

Energy Model supports now other devices like GPUs, DSPs, not only CPUs. Thus, update the description in the config option. Remove also unneeded "default n". If the "default" line is removed, it defaults to 'n'. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

PM: sleep: No need to check PF_WQ_WORKER in thaw_kernel_threads()

2021-01-27T18:20:17Z

Because PF_KTHREAD is set for all wq worker threads, it is not necessary to check PF_WQ_WORKER in addition to it in thaw_kernel_threads(), so stop doing that. Signed-off-by: Zqiang [ rjw: Subject and changelog rewrite ] Signed-off-by: Rafael J. Wysocki

PM: hibernate: flush swap writer after marking

2021-01-25T17:52:30Z

Flush the swap writer after, not before, marking the files, to ensure the signature is properly written. Fixes: 6f612af57821 ("PM / Hibernate: Group swap ops") Signed-off-by: Laurent Badel Cc: All applicable Signed-off-by: Rafael J. Wysocki

Merge tag 'pm-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2020-12-16T00:30:31Z

Pull power management updates from Rafael Wysocki: "These update cpufreq (core and drivers), cpuidle (polling state implementation and the PSCI driver), the OPP (operating performance points) framework, devfreq (core and drivers), the power capping RAPL (Running Average Power Limit) driver, the Energy Model support, the generic power domains (genpd) framework, the ACPI device power management, the core system-wide suspend code and power management utilities. Specifics: - Use local_clock() instead of jiffies in the cpufreq statistics to improve accuracy (Viresh Kumar). - Fix up OPP usage in the cpufreq-dt and qcom-cpufreq-nvmem cpufreq drivers (Viresh Kumar). - Clean up the cpufreq core, the intel_pstate driver and the schedutil cpufreq governor (Rafael Wysocki). - Fix up error code paths in the sti-cpufreq and mediatek cpufreq drivers (Yangtao Li, Qinglang Miao). - Fix cpufreq_online() to return error codes instead of success (0) in all cases when it fails (Wang ShaoBo). - Add mt8167 support to the mediatek cpufreq driver and blacklist mt8516 in the cpufreq-dt-platdev driver (Fabien Parent). - Modify the tegra194 cpufreq driver to always return values from the frequency table as the current frequency and clean up that driver (Sumit Gupta, Jon Hunter). - Modify the arm_scmi cpufreq driver to allow it to discover the power scale present in the performance protocol and provide this information to the Energy Model (Lukasz Luba). - Add missing MODULE_DEVICE_TABLE to several cpufreq drivers (Pali Rohár). - Clean up the CPPC cpufreq driver (Ionela Voinescu). - Fix NVMEM_IMX_OCOTP dependency in the imx cpufreq driver (Arnd Bergmann). - Rework the poling interval selection for the polling state in cpuidle (Mel Gorman). - Enable suspend-to-idle for PSCI OSI mode in the PSCI cpuidle driver (Ulf Hansson). - Modify the OPP framework to support empty (node-less) OPP tables in DT for passing dependency information (Nicola Mazzucato). - Fix potential lockdep issue in the OPP core and clean up the OPP core (Viresh Kumar). - Modify dev_pm_opp_put_regulators() to accept a NULL argument and update its users accordingly (Viresh Kumar). - Add frequency changes tracepoint to devfreq (Matthias Kaehlcke). - Add support for governor feature flags to devfreq, make devfreq sysfs file permissions depend on the governor and clean up the devfreq core (Chanwoo Choi). - Clean up the tegra20 devfreq driver and deprecate it to allow another driver based on EMC_STAT to be used instead of it (Dmitry Osipenko). - Add interconnect support to the tegra30 devfreq driver, allow it to take the interconnect and OPP information from DT and clean it up (Dmitry Osipenko). - Add interconnect support to the exynos-bus devfreq driver along with interconnect properties documentation (Sylwester Nawrocki). - Add suport for AMD Fam17h and Fam19h processors to the RAPL power capping driver (Victor Ding, Kim Phillips). - Fix handling of overly long constraint names in the powercap framework (Lukasz Luba). - Fix the wakeup configuration handling for bridges in the ACPI device power management core (Rafael Wysocki). - Add support for using an abstract scale for power units in the Energy Model (EM) and document it (Lukasz Luba). - Add em_cpu_energy() micro-optimization to the EM (Pavankumar Kondeti). - Modify the generic power domains (genpd) framwework to support suspend-to-idle (Ulf Hansson). - Fix creation of debugfs nodes in genpd (Thierry Strudel). - Clean up genpd (Lina Iyer). - Clean up the core system-wide suspend code and make it print driver flags for devices with debug enabled (Alex Shi, Patrice Chotard, Chen Yu). - Modify the ACPI system reboot code to make it prepare for system power off to avoid confusing the platform firmware (Kai-Heng Feng). - Update the pm-graph (multiple changes, mostly usability-related) and cpupower (online and offline CPU information support) PM utilities (Todd Brandt, Brahadambal Srinivasan)" * tag 'pm-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (86 commits) cpufreq: Fix cpufreq_online() return value on errors cpufreq: Fix up several kerneldoc comments cpufreq: stats: Use local_clock() instead of jiffies cpufreq: schedutil: Simplify sugov_update_next_freq() cpufreq: intel_pstate: Simplify intel_cpufreq_update_pstate() PM: domains: create debugfs nodes when adding power domains opp: of: Allow empty opp-table with opp-shared dt-bindings: opp: Allow empty OPP tables media: venus: dev_pm_opp_put_*() accepts NULL argument drm/panfrost: dev_pm_opp_put_*() accepts NULL argument drm/lima: dev_pm_opp_put_*() accepts NULL argument PM / devfreq: exynos: dev_pm_opp_put_*() accepts NULL argument cpufreq: qcom-cpufreq-nvmem: dev_pm_opp_put_*() accepts NULL argument cpufreq: dt: dev_pm_opp_put_regulators() accepts NULL argument opp: Allow dev_pm_opp_put_*() APIs to accept NULL opp_table opp: Don't create an OPP table from dev_pm_opp_get_opp_table() cpufreq: dt: Don't (ab)use dev_pm_opp_get_opp_table() to create OPP table opp: Reduce the size of critical section in _opp_kref_release() PM / EM: Micro optimization in em_cpu_energy cpufreq: arm_scmi: Discover the power scale in performance protocol ...