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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 19:40:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 19:40:31 -0700
commit8f5e823f9131a430b12f73e9436d7486e20c16f5 (patch)
treeec3f03c236182d113dd71b1b7b59be73e54ebab1 /Documentation/admin-guide
parent59df1c2bdecb0d1aaadfb8533df4bea528ee4952 (diff)
parente07095c9bbcd296401bec8b6852d258d7c926969 (diff)
Merge tag 'pm-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki: "These fix the (Intel-specific) Performance and Energy Bias Hint (EPB) handling and expose it to user space via sysfs, fix and clean up several cpufreq drivers, add support for two new chips to the qoriq cpufreq driver, fix, simplify and clean up the cpufreq core and the schedutil governor, add support for "CPU" domains to the generic power domains (genpd) framework and provide low-level PSCI firmware support for that feature, fix the exynos cpuidle driver and fix a couple of issues in the devfreq subsystem and clean it up. Specifics: - Fix the handling of Performance and Energy Bias Hint (EPB) on Intel processors and expose it to user space via sysfs to avoid having to access it through the generic MSR I/F (Rafael Wysocki). - Improve the handling of global turbo changes made by the platform firmware in the intel_pstate driver (Rafael Wysocki). - Convert some slow-path static_cpu_has() callers to boot_cpu_has() in cpufreq (Borislav Petkov). - Fix the frequency calculation loop in the armada-37xx cpufreq driver (Gregory CLEMENT). - Fix possible object reference leaks in multuple cpufreq drivers (Wen Yang). - Fix kerneldoc comment in the centrino cpufreq driver (dongjian). - Clean up the ACPI and maple cpufreq drivers (Viresh Kumar, Mohan Kumar). - Add support for lx2160a and ls1028a to the qoriq cpufreq driver (Vabhav Sharma, Yuantian Tang). - Fix kobject memory leak in the cpufreq core (Viresh Kumar). - Simplify the IOwait boosting in the schedutil cpufreq governor and rework the TSC cpufreq notifier on x86 (Rafael Wysocki). - Clean up the cpufreq core and statistics code (Yue Hu, Kyle Lin). - Improve the cpufreq documentation, add SPDX license tags to some PM documentation files and unify copyright notices in them (Rafael Wysocki). - Add support for "CPU" domains to the generic power domains (genpd) framework and provide low-level PSCI firmware support for that feature (Ulf Hansson). - Rearrange the PSCI firmware support code and add support for SYSTEM_RESET2 to it (Ulf Hansson, Sudeep Holla). - Improve genpd support for devices in multiple power domains (Ulf Hansson). - Unify target residency for the AFTR and coupled AFTR states in the exynos cpuidle driver (Marek Szyprowski). - Introduce new helper routine in the operating performance points (OPP) framework (Andrew-sh.Cheng). - Add support for passing on-die termination (ODT) and auto power down parameters from the kernel to Trusted Firmware-A (TF-A) to the rk3399_dmc devfreq driver (Enric Balletbo i Serra). - Add tracing to devfreq (Lukasz Luba). - Make the exynos-bus devfreq driver suspend all devices on system shutdown (Marek Szyprowski). - Fix a few minor issues in the devfreq subsystem and clean it up somewhat (Enric Balletbo i Serra, MyungJoo Ham, Rob Herring, Saravana Kannan, Yangtao Li). - Improve system wakeup diagnostics (Stephen Boyd). - Rework filesystem sync messages emitted during system suspend and hibernation (Harry Pan)" * tag 'pm-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (72 commits) cpufreq: Fix kobject memleak cpufreq: armada-37xx: fix frequency calculation for opp cpufreq: centrino: Fix centrino_setpolicy() kerneldoc comment cpufreq: qoriq: add support for lx2160a x86: tsc: Rework time_cpufreq_notifier() PM / Domains: Allow to attach a CPU via genpd_dev_pm_attach_by_id|name() PM / Domains: Search for the CPU device outside the genpd lock PM / Domains: Drop unused in-parameter to some genpd functions PM / Domains: Use the base device for driver_deferred_probe_check_state() cpufreq: qoriq: Add ls1028a chip support PM / Domains: Enable genpd_dev_pm_attach_by_id|name() for single PM domain PM / Domains: Allow OF lookup for multi PM domain case from ->attach_dev() PM / Domains: Don't kfree() the virtual device in the error path cpufreq: Move ->get callback check outside of __cpufreq_get() PM / Domains: remove unnecessary unlikely() cpufreq: Remove needless bios_limit check in show_bios_limit() drivers/cpufreq/acpi-cpufreq.c: This fixes the following checkpatch warning firmware/psci: add support for SYSTEM_RESET2 PM / devfreq: add tracing for scheduling work trace: events: add devfreq trace event file ...
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/pm/cpufreq.rst18
-rw-r--r--Documentation/admin-guide/pm/cpuidle.rst8
-rw-r--r--Documentation/admin-guide/pm/index.rst2
-rw-r--r--Documentation/admin-guide/pm/intel_epb.rst41
-rw-r--r--Documentation/admin-guide/pm/intel_pstate.rst32
-rw-r--r--Documentation/admin-guide/pm/sleep-states.rst8
-rw-r--r--Documentation/admin-guide/pm/strategies.rst8
-rw-r--r--Documentation/admin-guide/pm/system-wide.rst2
-rw-r--r--Documentation/admin-guide/pm/working-state.rst3
9 files changed, 100 insertions, 22 deletions
diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst
index 7eca9026a9ed..0c74a7784964 100644
--- a/Documentation/admin-guide/pm/cpufreq.rst
+++ b/Documentation/admin-guide/pm/cpufreq.rst
@@ -1,3 +1,6 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
.. |struct cpufreq_policy| replace:: :c:type:`struct cpufreq_policy <cpufreq_policy>`
.. |intel_pstate| replace:: :doc:`intel_pstate <intel_pstate>`
@@ -5,9 +8,10 @@
CPU Performance Scaling
=======================
-::
+:Copyright: |copy| 2017 Intel Corporation
+
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
- Copyright (c) 2017 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The Concept of CPU Performance Scaling
======================================
@@ -396,8 +400,8 @@ RT or deadline scheduling classes, the governor will increase the frequency to
the allowed maximum (that is, the ``scaling_max_freq`` policy limit). In turn,
if it is invoked by the CFS scheduling class, the governor will use the
Per-Entity Load Tracking (PELT) metric for the root control group of the
-given CPU as the CPU utilization estimate (see the `Per-entity load tracking`_
-LWN.net article for a description of the PELT mechanism). Then, the new
+given CPU as the CPU utilization estimate (see the *Per-entity load tracking*
+LWN.net article [1]_ for a description of the PELT mechanism). Then, the new
CPU frequency to apply is computed in accordance with the formula
f = 1.25 * ``f_0`` * ``util`` / ``max``
@@ -698,4 +702,8 @@ hardware feature (e.g. all Intel ones), even if the
:c:macro:`CONFIG_X86_ACPI_CPUFREQ_CPB` configuration option is set.
-.. _Per-entity load tracking: https://lwn.net/Articles/531853/
+References
+==========
+
+.. [1] Jonathan Corbet, *Per-entity load tracking*,
+ https://lwn.net/Articles/531853/
diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst
index 9c58b35a81cb..e70b365dbc60 100644
--- a/Documentation/admin-guide/pm/cpuidle.rst
+++ b/Documentation/admin-guide/pm/cpuidle.rst
@@ -1,3 +1,6 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
.. |struct cpuidle_state| replace:: :c:type:`struct cpuidle_state <cpuidle_state>`
.. |cpufreq| replace:: :doc:`CPU Performance Scaling <cpufreq>`
@@ -5,9 +8,10 @@
CPU Idle Time Management
========================
-::
+:Copyright: |copy| 2018 Intel Corporation
+
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
- Copyright (c) 2018 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Concepts
========
diff --git a/Documentation/admin-guide/pm/index.rst b/Documentation/admin-guide/pm/index.rst
index 49237ac73442..39f8f9f81e7a 100644
--- a/Documentation/admin-guide/pm/index.rst
+++ b/Documentation/admin-guide/pm/index.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: GPL-2.0
+
================
Power Management
================
diff --git a/Documentation/admin-guide/pm/intel_epb.rst b/Documentation/admin-guide/pm/intel_epb.rst
new file mode 100644
index 000000000000..005121167af7
--- /dev/null
+++ b/Documentation/admin-guide/pm/intel_epb.rst
@@ -0,0 +1,41 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+======================================
+Intel Performance and Energy Bias Hint
+======================================
+
+:Copyright: |copy| 2019 Intel Corporation
+
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+
+
+.. kernel-doc:: arch/x86/kernel/cpu/intel_epb.c
+ :doc: overview
+
+Intel Performance and Energy Bias Attribute in ``sysfs``
+========================================================
+
+The Intel Performance and Energy Bias Hint (EPB) value for a given (logical) CPU
+can be checked or updated through a ``sysfs`` attribute (file) under
+:file:`/sys/devices/system/cpu/cpu<N>/power/`, where the CPU number ``<N>``
+is allocated at the system initialization time:
+
+``energy_perf_bias``
+ Shows the current EPB value for the CPU in a sliding scale 0 - 15, where
+ a value of 0 corresponds to a hint preference for highest performance
+ and a value of 15 corresponds to the maximum energy savings.
+
+ In order to update the EPB value for the CPU, this attribute can be
+ written to, either with a number in the 0 - 15 sliding scale above, or
+ with one of the strings: "performance", "balance-performance", "normal",
+ "balance-power", "power" that represent values reflected by their
+ meaning.
+
+ This attribute is present for all online CPUs supporting the EPB
+ feature.
+
+Note that while the EPB interface to the processor is defined at the logical CPU
+level, the physical register backing it may be shared by multiple CPUs (for
+example, SMT siblings or cores in one package). For this reason, updating the
+EPB value for one CPU may cause the EPB values for other CPUs to change.
diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin-guide/pm/intel_pstate.rst
index ec0f7c111f65..67e414e34f37 100644
--- a/Documentation/admin-guide/pm/intel_pstate.rst
+++ b/Documentation/admin-guide/pm/intel_pstate.rst
@@ -1,10 +1,13 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
===============================================
``intel_pstate`` CPU Performance Scaling Driver
===============================================
-::
+:Copyright: |copy| 2017 Intel Corporation
- Copyright (c) 2017 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
General Information
@@ -20,11 +23,10 @@ you have not done that yet.]
For the processors supported by ``intel_pstate``, the P-state concept is broader
than just an operating frequency or an operating performance point (see the
-`LinuxCon Europe 2015 presentation by Kristen Accardi <LCEU2015_>`_ for more
+LinuxCon Europe 2015 presentation by Kristen Accardi [1]_ for more
information about that). For this reason, the representation of P-states used
by ``intel_pstate`` internally follows the hardware specification (for details
-refer to `Intel® 64 and IA-32 Architectures Software Developer’s Manual
-Volume 3: System Programming Guide <SDM_>`_). However, the ``CPUFreq`` core
+refer to Intel Software Developer’s Manual [2]_). However, the ``CPUFreq`` core
uses frequencies for identifying operating performance points of CPUs and
frequencies are involved in the user space interface exposed by it, so
``intel_pstate`` maps its internal representation of P-states to frequencies too
@@ -561,9 +563,9 @@ or to pin every task potentially sensitive to them to a specific CPU.]
On the majority of systems supported by ``intel_pstate``, the ACPI tables
provided by the platform firmware contain ``_PSS`` objects returning information
-that can be used for CPU performance scaling (refer to the `ACPI specification`_
-for details on the ``_PSS`` objects and the format of the information returned
-by them).
+that can be used for CPU performance scaling (refer to the ACPI specification
+[3]_ for details on the ``_PSS`` objects and the format of the information
+returned by them).
The information returned by the ACPI ``_PSS`` objects is used by the
``acpi-cpufreq`` scaling driver. On systems supported by ``intel_pstate``
@@ -728,6 +730,14 @@ P-state is called, the ``ftrace`` filter can be set to to
<idle>-0 [000] ..s. 2537.654843: intel_pstate_set_pstate <-intel_pstate_timer_func
-.. _LCEU2015: http://events.linuxfoundation.org/sites/events/files/slides/LinuxConEurope_2015.pdf
-.. _SDM: http://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-system-programming-manual-325384.html
-.. _ACPI specification: http://www.uefi.org/sites/default/files/resources/ACPI_6_1.pdf
+References
+==========
+
+.. [1] Kristen Accardi, *Balancing Power and Performance in the Linux Kernel*,
+ http://events.linuxfoundation.org/sites/events/files/slides/LinuxConEurope_2015.pdf
+
+.. [2] *Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 3: System Programming Guide*,
+ http://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-system-programming-manual-325384.html
+
+.. [3] *Advanced Configuration and Power Interface Specification*,
+ https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
diff --git a/Documentation/admin-guide/pm/sleep-states.rst b/Documentation/admin-guide/pm/sleep-states.rst
index dbf5acd49f35..cd3a28cb81f4 100644
--- a/Documentation/admin-guide/pm/sleep-states.rst
+++ b/Documentation/admin-guide/pm/sleep-states.rst
@@ -1,10 +1,14 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
===================
System Sleep States
===================
-::
+:Copyright: |copy| 2017 Intel Corporation
+
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
- Copyright (c) 2017 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Sleep states are global low-power states of the entire system in which user
space code cannot be executed and the overall system activity is significantly
diff --git a/Documentation/admin-guide/pm/strategies.rst b/Documentation/admin-guide/pm/strategies.rst
index afe4d3f831fe..dd0362e32fa5 100644
--- a/Documentation/admin-guide/pm/strategies.rst
+++ b/Documentation/admin-guide/pm/strategies.rst
@@ -1,10 +1,14 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
===========================
Power Management Strategies
===========================
-::
+:Copyright: |copy| 2017 Intel Corporation
+
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
- Copyright (c) 2017 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The Linux kernel supports two major high-level power management strategies.
diff --git a/Documentation/admin-guide/pm/system-wide.rst b/Documentation/admin-guide/pm/system-wide.rst
index 0c81e4c5de39..2b1f987b34f0 100644
--- a/Documentation/admin-guide/pm/system-wide.rst
+++ b/Documentation/admin-guide/pm/system-wide.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: GPL-2.0
+
============================
System-Wide Power Management
============================
diff --git a/Documentation/admin-guide/pm/working-state.rst b/Documentation/admin-guide/pm/working-state.rst
index b6cef9b5e961..fc298eb1234b 100644
--- a/Documentation/admin-guide/pm/working-state.rst
+++ b/Documentation/admin-guide/pm/working-state.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: GPL-2.0
+
==============================
Working-State Power Management
==============================
@@ -8,3 +10,4 @@ Working-State Power Management
cpuidle
cpufreq
intel_pstate
+ intel_epb