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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-02-21 12:13:58 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-02-21 12:13:58 -0800 |
commit | 2504ba8b01634319a6f95b7fa9bf9c101437e158 (patch) | |
tree | d479a6cc799f958c3961d10d0149d63649901f40 /Documentation/admin-guide | |
parent | 4a7d37e824f57dbace61abf62f53843800bd245c (diff) | |
parent | dd855f01e8d194d2dfeda36b620203c623c10430 (diff) | |
download | lwn-2504ba8b01634319a6f95b7fa9bf9c101437e158.tar.gz lwn-2504ba8b01634319a6f95b7fa9bf9c101437e158.zip |
Merge tag 'pm-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"These add EPP support to the AMD P-state cpufreq driver, add support
for new platforms to the Intel RAPL power capping driver, intel_idle
and the Qualcomm cpufreq driver, enable thermal cooling for Tegra194,
drop the custom cpufreq driver for loongson1 that is not necessary any
more (and the corresponding cpufreq platform device), fix assorted
issues and clean up code.
Specifics:
- Add EPP support to the AMD P-state cpufreq driver (Perry Yuan, Wyes
Karny, Arnd Bergmann, Bagas Sanjaya)
- Drop the custom cpufreq driver for loongson1 that is not necessary
any more and the corresponding cpufreq platform device (Keguang
Zhang)
- Remove "select SRCU" from system sleep, cpufreq and OPP Kconfig
entries (Paul E. McKenney)
- Enable thermal cooling for Tegra194 (Yi-Wei Wang)
- Register module device table and add missing compatibles for
cpufreq-qcom-hw (Nícolas F. R. A. Prado, Abel Vesa and Luca Weiss)
- Various dt binding updates for qcom-cpufreq-nvmem and
opp-v2-kryo-cpu (Christian Marangi)
- Make kobj_type structure in the cpufreq core constant (Thomas
Weißschuh)
- Make cpufreq_unregister_driver() return void (Uwe Kleine-König)
- Make the TEO cpuidle governor check CPU utilization in order to
refine idle state selection (Kajetan Puchalski)
- Make Kconfig select the haltpoll cpuidle governor when the haltpoll
cpuidle driver is selected and replace a default_idle() call in
that driver with arch_cpu_idle() to allow MWAIT to be used (Li
RongQing)
- Add Emerald Rapids Xeon support to the intel_idle driver (Artem
Bityutskiy)
- Add ARCH_SUSPEND_POSSIBLE dependencies for ARMv4 cpuidle drivers to
avoid randconfig build failures (Arnd Bergmann)
- Make kobj_type structures used in the cpuidle sysfs interface
constant (Thomas Weißschuh)
- Make the cpuidle driver registration code update microsecond values
of idle state parameters in accordance with their nanosecond values
if they are provided (Rafael Wysocki)
- Make the PSCI cpuidle driver prevent topology CPUs from being
suspended on PREEMPT_RT (Krzysztof Kozlowski)
- Document that pm_runtime_force_suspend() cannot be used with
DPM_FLAG_SMART_SUSPEND (Richard Fitzgerald)
- Add EXPORT macros for exporting PM functions from drivers (Richard
Fitzgerald)
- Remove /** from non-kernel-doc comments in hibernation code (Randy
Dunlap)
- Fix possible name leak in powercap_register_zone() (Yang Yingliang)
- Add Meteor Lake and Emerald Rapids support to the intel_rapl power
capping driver (Zhang Rui)
- Modify the idle_inject power capping facility to support 100% idle
injection (Srinivas Pandruvada)
- Fix large time windows handling in the intel_rapl power capping
driver (Zhang Rui)
- Fix memory leaks with using debugfs_lookup() in the generic PM
domains and Energy Model code (Greg Kroah-Hartman)
- Add missing 'cache-unified' property in the example for kryo OPP
bindings (Rob Herring)
- Fix error checking in opp_migrate_dentry() (Qi Zheng)
- Let qcom,opp-fuse-level be a 2-long array for qcom SoCs (Konrad
Dybcio)
- Modify some power management utilities to use the canonical ftrace
path (Ross Zwisler)
- Correct spelling problems for Documentation/power/ as reported by
codespell (Randy Dunlap)"
* tag 'pm-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (53 commits)
Documentation: amd-pstate: disambiguate user space sections
cpufreq: amd-pstate: Fix invalid write to MSR_AMD_CPPC_REQ
dt-bindings: opp: opp-v2-kryo-cpu: enlarge opp-supported-hw maximum
dt-bindings: cpufreq: qcom-cpufreq-nvmem: make cpr bindings optional
dt-bindings: cpufreq: qcom-cpufreq-nvmem: specify supported opp tables
PM: Add EXPORT macros for exporting PM functions
cpuidle: psci: Do not suspend topology CPUs on PREEMPT_RT
MIPS: loongson32: Drop obsolete cpufreq platform device
powercap: intel_rapl: Fix handling for large time window
cpuidle: driver: Update microsecond values of state parameters as needed
cpuidle: sysfs: make kobj_type structures constant
cpuidle: add ARCH_SUSPEND_POSSIBLE dependencies
PM: EM: fix memory leak with using debugfs_lookup()
PM: domains: fix memory leak with using debugfs_lookup()
cpufreq: Make kobj_type structure constant
cpufreq: davinci: Fix clk use after free
cpufreq: amd-pstate: avoid uninitialized variable use
cpufreq: Make cpufreq_unregister_driver() return void
OPP: fix error checking in opp_migrate_dentry()
dt-bindings: cpufreq: cpufreq-qcom-hw: Add SM8550 compatible
...
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 7 | ||||
-rw-r--r-- | Documentation/admin-guide/pm/amd-pstate.rst | 78 |
2 files changed, 81 insertions, 4 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2b0692a642a7..8870a29f92a8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -7041,3 +7041,10 @@ management firmware translates the requests into actual hardware states (core frequency, data fabric and memory clocks etc.) + active + Use amd_pstate_epp driver instance as the scaling driver, + driver provides a hint to the hardware if software wants + to bias toward performance (0x0) or energy efficiency (0xff) + to the CPPC firmware. then CPPC power algorithm will + calculate the runtime workload and adjust the realtime cores + frequency. diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index 5376d53faaa8..d143e72cf93e 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -230,8 +230,8 @@ with :c:macro:`MSR_AMD_CPPC_ENABLE` or ``cppc_set_enable``, it will respond to the request from AMD P-States. -User Space Interface in ``sysfs`` -================================== +User Space Interface in ``sysfs`` - Per-policy control +====================================================== ``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to control its functionality at the system level. They are located in the @@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC Performance Capability <perf_cap_>`_.) This attribute is read-only. +``energy_performance_available_preferences`` + +A list of all the supported EPP preferences that could be used for +``energy_performance_preference`` on this system. +These profiles represent different hints that are provided +to the low-level firmware about the user's desired energy vs efficiency +tradeoff. ``default`` represents the epp value is set by platform +firmware. This attribute is read-only. + +``energy_performance_preference`` + +The current energy performance preference can be read from this attribute. +and user can change current preference according to energy or performance needs +Please get all support profiles list from +``energy_performance_available_preferences`` attribute, all the profiles are +integer values defined between 0 to 255 when EPP feature is enabled by platform +firmware, if EPP feature is disabled, driver will ignore the written value +This attribute is read-write. + Other performance and frequency values can be read back from ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`. @@ -280,8 +299,30 @@ module which supports the new AMD P-States mechanism on most of the future AMD platforms. The AMD P-States mechanism is the more performance and energy efficiency frequency management method on AMD processors. -Kernel Module Options for ``amd-pstate`` -========================================= + +AMD Pstate Driver Operation Modes +================================= + +``amd_pstate`` CPPC has two operation modes: CPPC Autonomous(active) mode and +CPPC non-autonomous(passive) mode. +active mode and passive mode can be chosen by different kernel parameters. +When in Autonomous mode, CPPC ignores requests done in the Desired Performance +Target register and takes into account only the values set to the Minimum requested +performance, Maximum requested performance, and Energy Performance Preference +registers. When Autonomous is disabled, it only considers the Desired Performance Target. + +Active Mode +------------ + +``amd_pstate=active`` + +This is the low-level firmware control mode which is implemented by ``amd_pstate_epp`` +driver with ``amd_pstate=active`` passed to the kernel in the command line. +In this mode, ``amd_pstate_epp`` driver provides a hint to the hardware if software +wants to bias toward performance (0x0) or energy efficiency (0xff) to the CPPC firmware. +then CPPC power algorithm will calculate the runtime workload and adjust the realtime +cores frequency according to the power supply and thermal, core voltage and some other +hardware conditions. Passive Mode ------------ @@ -298,6 +339,35 @@ processor must provide at least nominal performance requested and go higher if c operating conditions allow. +User Space Interface in ``sysfs`` - General +=========================================== + +Global Attributes +----------------- + +``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to +control its functionality at the system level. They are located in the +``/sys/devices/system/cpu/amd-pstate/`` directory and affect all CPUs. + +``status`` + Operation mode of the driver: "active", "passive" or "disable". + + "active" + The driver is functional and in the ``active mode`` + + "passive" + The driver is functional and in the ``passive mode`` + + "disable" + The driver is unregistered and not functional now. + + This attribute can be written to in order to change the driver's + operation mode or to unregister it. The string written to it must be + one of the possible values of it and, if successful, writing one of + these values to the sysfs file will cause the driver to switch over + to the operation mode represented by that string - or to be + unregistered in the "disable" case. + ``cpupower`` tool support for ``amd-pstate`` =============================================== |