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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-21 02:41:31 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-21 02:41:31 +0100 |
commit | 02c3de1105228e367320e7fdeffbf511904f398c (patch) | |
tree | d0861ed0752806c6c85e72749734dad9914a8cd9 /Documentation/cpu-freq/user-guide.txt | |
parent | Merge tag 'leds_for_4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/j.... (diff) | |
parent | Merge branch 'pm-tools' (diff) | |
download | linux-02c3de1105228e367320e7fdeffbf511904f398c.tar.xz linux-02c3de1105228e367320e7fdeffbf511904f398c.zip |
Merge tag 'pm-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"The majority of changes go into the Operating Performance Points (OPP)
framework and cpufreq this time, followed by devfreq and some
scattered updates all over.
The OPP changes are mostly related to switching over from RCU-based
synchronization, that turned out to be overly complicated and
problematic, to reference counting using krefs.
In the cpufreq land there are core cleanups, documentation updates, a
new driver for Broadcom BMIPS SoCs, a new cpufreq-dt sub-driver for TI
SoCs that require special handling, ARM64 SoCs support for the qoriq
driver, intel_pstate updates, powernv driver update and assorted
fixes.
The devfreq changes are mostly fixes related to the sysfs interface
and some Exynos drivers updates.
Apart from that, the cpuidle menu governor will support per-CPU PM QoS
constraints for the wakeup latency now, some bugs in the wakeup IRQs
framework are fixed, the generic power domains framework should handle
asynchronous invocations of *noirq suspend/resume callbacks from now
on, the analyze_suspend.py script is updated and there is a new tool
for intel_pstate diagnostics.
Specifics:
- Operating Performance Points (OPP) framework fixes, cleanups and
switch over from RCU-based synchronization to reference counting
using krefs (Viresh Kumar, Wei Yongjun, Dave Gerlach)
- cpufreq core cleanups and documentation updates (Viresh Kumar,
Rafael Wysocki)
- New cpufreq driver for Broadcom BMIPS SoCs (Markus Mayer)
- New cpufreq-dt sub-driver for TI SoCs requiring special handling,
like in the AM335x, AM437x, DRA7x, and AM57x families, along with
new DT bindings for it (Dave Gerlach, Paul Gortmaker)
- ARM64 SoCs support for the qoriq cpufreq driver (Tang Yuantian)
- intel_pstate driver updates including a new sysfs knob to control
the driver's operation mode and fixes related to the no_turbo sysfs
knob and the hardware-managed P-states feature support (Rafael
Wysocki, Srinivas Pandruvada)
- New interface to export ultra-turbo frequencies for the powernv
cpufreq driver (Shilpasri Bhat)
- Assorted fixes for cpufreq drivers (Arnd Bergmann, Dan Carpenter,
Wei Yongjun)
- devfreq core fixes, mostly related to the sysfs interface exported
by it (Chanwoo Choi, Chris Diamand)
- Updates of the exynos-bus and exynos-ppmu devfreq drivers (Chanwoo
Choi)
- Device PM QoS extension to support CPUs and support for per-CPU
wakeup (device resume) latency constraints in the cpuidle menu
governor (Alex Shi)
- Wakeup IRQs framework fixes (Grygorii Strashko)
- Generic power domains framework update including a fix to make it
handle asynchronous invocations of *noirq suspend/resume callbacks
correctly (Ulf Hansson, Geert Uytterhoeven)
- Assorted fixes and cleanups in the core suspend/hibernate code, PM
QoS framework and x86 ACPI idle support code (Corentin Labbe, Geert
Uytterhoeven, Geliang Tang, John Keeping, Nick Desaulniers)
- Update of the analyze_suspend.py script is updated to version 4.5
offering multiple improvements (Todd Brandt)
- New tool for intel_pstate diagnostics using the pstate_sample
tracepoint (Doug Smythies)"
* tag 'pm-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (85 commits)
MAINTAINERS: cpufreq: add bmips-cpufreq.c
PM / QoS: Fix memory leak on resume_latency.notifiers
PM / Documentation: Spelling s/wrtie/write/
PM / sleep: Fix test_suspend after sleep state rework
cpufreq: CPPC: add ACPI_PROCESSOR dependency
cpufreq: make ti-cpufreq explicitly non-modular
cpufreq: Do not clear real_cpus mask on policy init
tools/power/x86: Debug utility for intel_pstate driver
AnalyzeSuspend: fix drag and zoom bug in javascript
PM / wakeirq: report a wakeup_event on dedicated wekup irq
PM / wakeirq: Fix spurious wake-up events for dedicated wakeirqs
PM / wakeirq: Enable dedicated wakeirq for suspend
cpufreq: dt: Don't use generic platdev driver for ti-cpufreq platforms
cpufreq: ti: Add cpufreq driver to determine available OPPs at runtime
Documentation: dt: add bindings for ti-cpufreq
PM / OPP: Expose _of_get_opp_desc_node as dev_pm_opp API
cpufreq: qoriq: Don't look at clock implementation details
cpufreq: qoriq: add ARM64 SoCs support
PM / Domains: Provide dummy governors if CONFIG_PM_GENERIC_DOMAINS=n
cpufreq: brcmstb-avs-cpufreq: remove unnecessary platform_set_drvdata()
...
Diffstat (limited to 'Documentation/cpu-freq/user-guide.txt')
-rw-r--r-- | Documentation/cpu-freq/user-guide.txt | 60 |
1 files changed, 32 insertions, 28 deletions
diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt index 109e97bbab77..107f6fdd7d14 100644 --- a/Documentation/cpu-freq/user-guide.txt +++ b/Documentation/cpu-freq/user-guide.txt @@ -18,7 +18,7 @@ Contents: --------- 1. Supported Architectures and Processors -1.1 ARM +1.1 ARM and ARM64 1.2 x86 1.3 sparc64 1.4 ppc @@ -37,16 +37,10 @@ Contents: 1. Supported Architectures and Processors ========================================= -1.1 ARM -------- - -The following ARM processors are supported by cpufreq: - -ARM Integrator -ARM-SA1100 -ARM-SA1110 -Intel PXA +1.1 ARM and ARM64 +----------------- +Almost all ARM and ARM64 platforms support CPU frequency scaling. 1.2 x86 ------- @@ -69,6 +63,7 @@ Transmeta Crusoe Transmeta Efficeon VIA Cyrix 3 / C3 various processors on some ACPI 2.0-compatible systems [*] +And many more [*] Only if "ACPI Processor Performance States" are available to the ACPI<->BIOS interface. @@ -147,10 +142,19 @@ mounted it at /sys, the cpufreq interface is located in a subdirectory "cpufreq" within the cpu-device directory (e.g. /sys/devices/system/cpu/cpu0/cpufreq/ for the first CPU). +affected_cpus : List of Online CPUs that require software + coordination of frequency. + +cpuinfo_cur_freq : Current frequency of the CPU as obtained from + the hardware, in KHz. This is the frequency + the CPU actually runs at. + cpuinfo_min_freq : this file shows the minimum operating frequency the processor can run at(in kHz) + cpuinfo_max_freq : this file shows the maximum operating frequency the processor can run at(in kHz) + cpuinfo_transition_latency The time it takes on this CPU to switch between two frequencies in nano seconds. If unknown or known to be @@ -163,25 +167,30 @@ cpuinfo_transition_latency The time it takes on this CPU to userspace daemon. Make sure to not switch the frequency too often resulting in performance loss. -scaling_driver : this file shows what cpufreq driver is - used to set the frequency on this CPU + +related_cpus : List of Online + Offline CPUs that need software + coordination of frequency. + +scaling_available_frequencies : List of available frequencies, in KHz. scaling_available_governors : this file shows the CPUfreq governors available in this kernel. You can see the currently activated governor in +scaling_cur_freq : Current frequency of the CPU as determined by + the governor and cpufreq core, in KHz. This is + the frequency the kernel thinks the CPU runs + at. + +scaling_driver : this file shows what cpufreq driver is + used to set the frequency on this CPU + scaling_governor, and by "echoing" the name of another governor you can change it. Please note that some governors won't load - they only work on some specific architectures or processors. -cpuinfo_cur_freq : Current frequency of the CPU as obtained from - the hardware, in KHz. This is the frequency - the CPU actually runs at. - -scaling_available_frequencies : List of available frequencies, in KHz. - scaling_min_freq and scaling_max_freq show the current "policy limits" (in kHz). By echoing new values into these @@ -190,16 +199,11 @@ scaling_max_freq show the current "policy limits" (in first set scaling_max_freq, then scaling_min_freq. -affected_cpus : List of Online CPUs that require software - coordination of frequency. - -related_cpus : List of Online + Offline CPUs that need software - coordination of frequency. - -scaling_cur_freq : Current frequency of the CPU as determined by - the governor and cpufreq core, in KHz. This is - the frequency the kernel thinks the CPU runs - at. +scaling_setspeed This can be read to get the currently programmed + value by the governor. This can be written to + change the current frequency for a group of + CPUs, represented by a policy. This is supported + currently only by the userspace governor. bios_limit : If the BIOS tells the OS to limit a CPU to lower frequencies, the user can read out the |