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authorLinus Torvalds <torvalds@linux-foundation.org>2022-03-21 14:26:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-21 14:26:28 -0700
commit02b82b02c34321dde10d003aafcd831a769b2a8a (patch)
treeead9a121b6fb2d37bbcc054f711b09d5bd788518 /Documentation/admin-guide
parent242ba6656d604aa8dc87451fc08143cb28d5a587 (diff)
parentec3d8b8365e9865b43099e943ec5f0bc12f28f96 (diff)
downloadlinux-02b82b02c34321dde10d003aafcd831a769b2a8a.tar.bz2
Merge tag 'pm-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki: "These are mostly fixes and cleanups all over the code and a new piece of documentation for Intel uncore frequency scaling. Functionality-wise, the intel_idle driver will support Sapphire Rapids Xeons natively now (with some extra facilities for controlling C-states more precisely on those systems), virtual guests will take the ACPI S4 hardware signature into account by default, the intel_pstate driver will take the defualt EPP value from the firmware, cpupower utility will support the AMD P-state driver added in the previous cycle, and there is a new tracer utility for that driver. Specifics: - Allow device_pm_check_callbacks() to be called from interrupt context without issues (Dmitry Baryshkov). - Modify devm_pm_runtime_enable() to automatically handle pm_runtime_dont_use_autosuspend() at driver exit time (Douglas Anderson). - Make the schedutil cpufreq governor use to_gov_attr_set() instead of open coding it (Kevin Hao). - Replace acpi_bus_get_device() with acpi_fetch_acpi_dev() in the cpufreq longhaul driver (Rafael Wysocki). - Unify show() and store() naming in cpufreq and make it use __ATTR_XX (Lianjie Zhang). - Make the intel_pstate driver use the EPP value set by the firmware by default (Srinivas Pandruvada). - Re-order the init checks in the powernow-k8 cpufreq driver (Mario Limonciello). - Make the ACPI processor idle driver check for architectural support for LPI to avoid using it on x86 by mistake (Mario Limonciello). - Add Sapphire Rapids Xeon support to the intel_idle driver (Artem Bityutskiy). - Add 'preferred_cstates' module argument to the intel_idle driver to work around C1 and C1E handling issue on Sapphire Rapids (Artem Bityutskiy). - Add core C6 optimization on Sapphire Rapids to the intel_idle driver (Artem Bityutskiy). - Optimize the haltpoll cpuidle driver a bit (Li RongQing). - Remove leftover text from intel_idle() kerneldoc comment and fix up white space in intel_idle (Rafael Wysocki). - Fix load_image_and_restore() error path (Ye Bin). - Fix typos in comments in the system wakeup hadling code (Tom Rix). - Clean up non-kernel-doc comments in hibernation code (Jiapeng Chong). - Fix __setup handler error handling in system-wide suspend and hibernation core code (Randy Dunlap). - Add device name to suspend_report_result() (Youngjin Jang). - Make virtual guests honour ACPI S4 hardware signature by default (David Woodhouse). - Block power off of a parent PM domain unless child is in deepest state (Ulf Hansson). - Use dev_err_probe() to simplify error handling for generic PM domains (Ahmad Fatoum). - Fix sleep-in-atomic bug caused by genpd_debug_remove() (Shawn Guo). - Document Intel uncore frequency scaling (Srinivas Pandruvada). - Add DTPM hierarchy description (Daniel Lezcano). - Change the locking scheme in DTPM (Daniel Lezcano). - Fix dtpm_cpu cleanup at exit time and missing virtual DTPM pointer release (Daniel Lezcano). - Make dtpm_node_callback[] static (kernel test robot). - Fix spelling mistake "initialze" -> "initialize" in dtpm_create_hierarchy() (Colin Ian King). - Add tracer tool for the amd-pstate driver (Jinzhou Su). - Fix PC6 displaying in turbostat on some systems (Artem Bityutskiy). - Add AMD P-State support to the cpupower utility (Huang Rui)" * tag 'pm-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (58 commits) cpufreq: powernow-k8: Re-order the init checks cpuidle: intel_idle: Drop redundant backslash at line end cpuidle: intel_idle: Update intel_idle() kerneldoc comment PM: hibernate: Honour ACPI hardware signature by default for virtual guests cpufreq: intel_pstate: Use firmware default EPP cpufreq: unify show() and store() naming and use __ATTR_XX PM: core: keep irq flags in device_pm_check_callbacks() cpuidle: haltpoll: Call cpuidle_poll_state_init() later Documentation: amd-pstate: add tracer tool introduction tools/power/x86/amd_pstate_tracer: Add tracer tool for AMD P-state tools/power/x86/intel_pstate_tracer: make tracer as a module cpufreq: amd-pstate: Add more tracepoint for AMD P-State module PM: sleep: Add device name to suspend_report_result() turbostat: fix PC6 displaying on some systems intel_idle: add core C6 optimization for SPR intel_idle: add 'preferred_cstates' module argument intel_idle: add SPR support PM: runtime: Have devm_pm_runtime_enable() handle pm_runtime_dont_use_autosuspend() ACPI: processor idle: Check for architectural support for LPI cpuidle: PSCI: Move the `has_lpi` check to the beginning of the function ...
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/pm/amd-pstate.rst26
-rw-r--r--Documentation/admin-guide/pm/intel_uncore_frequency_scaling.rst60
-rw-r--r--Documentation/admin-guide/pm/working-state.rst1
3 files changed, 87 insertions, 0 deletions
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 2f066df4ee9c..1923cb25073b 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -369,6 +369,32 @@ governor (for the policies it is attached to), or by the ``CPUFreq`` core (for t
policies with other scaling governors).
+Tracer Tool
+-------------
+
+``amd_pstate_tracer.py`` can record and parse ``amd-pstate`` trace log, then
+generate performance plots. This utility can be used to debug and tune the
+performance of ``amd-pstate`` driver. The tracer tool needs to import intel
+pstate tracer.
+
+Tracer tool located in ``linux/tools/power/x86/amd_pstate_tracer``. It can be
+used in two ways. If trace file is available, then directly parse the file
+with command ::
+
+ ./amd_pstate_trace.py [-c cpus] -t <trace_file> -n <test_name>
+
+Or generate trace file with root privilege, then parse and plot with command ::
+
+ sudo ./amd_pstate_trace.py [-c cpus] -n <test_name> -i <interval> [-m kbytes]
+
+The test result can be found in ``results/test_name``. Following is the example
+about part of the output. ::
+
+ common_cpu common_secs common_usecs min_perf des_perf max_perf freq mperf apef tsc load duration_ms sample_num elapsed_time common_comm
+ CPU_005 712 116384 39 49 166 0.7565 9645075 2214891 38431470 25.1 11.646 469 2.496 kworker/5:0-40
+ CPU_006 712 116408 39 49 166 0.6769 8950227 1839034 37192089 24.06 11.272 470 2.496 kworker/6:0-1264
+
+
Reference
===========
diff --git a/Documentation/admin-guide/pm/intel_uncore_frequency_scaling.rst b/Documentation/admin-guide/pm/intel_uncore_frequency_scaling.rst
new file mode 100644
index 000000000000..09169d935835
--- /dev/null
+++ b/Documentation/admin-guide/pm/intel_uncore_frequency_scaling.rst
@@ -0,0 +1,60 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+==============================
+Intel Uncore Frequency Scaling
+==============================
+
+:Copyright: |copy| 2022 Intel Corporation
+
+:Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
+
+Introduction
+------------
+
+The uncore can consume significant amount of power in Intel's Xeon servers based
+on the workload characteristics. To optimize the total power and improve overall
+performance, SoCs have internal algorithms for scaling uncore frequency. These
+algorithms monitor workload usage of uncore and set a desirable frequency.
+
+It is possible that users have different expectations of uncore performance and
+want to have control over it. The objective is similar to allowing users to set
+the scaling min/max frequencies via cpufreq sysfs to improve CPU performance.
+Users may have some latency sensitive workloads where they do not want any
+change to uncore frequency. Also, users may have workloads which require
+different core and uncore performance at distinct phases and they may want to
+use both cpufreq and the uncore scaling interface to distribute power and
+improve overall performance.
+
+Sysfs Interface
+---------------
+
+To control uncore frequency, a sysfs interface is provided in the directory:
+`/sys/devices/system/cpu/intel_uncore_frequency/`.
+
+There is one directory for each package and die combination as the scope of
+uncore scaling control is per die in multiple die/package SoCs or per
+package for single die per package SoCs. The name represents the
+scope of control. For example: 'package_00_die_00' is for package id 0 and
+die 0.
+
+Each package_*_die_* contains the following attributes:
+
+``initial_max_freq_khz``
+ Out of reset, this attribute represent the maximum possible frequency.
+ This is a read-only attribute. If users adjust max_freq_khz,
+ they can always go back to maximum using the value from this attribute.
+
+``initial_min_freq_khz``
+ Out of reset, this attribute represent the minimum possible frequency.
+ This is a read-only attribute. If users adjust min_freq_khz,
+ they can always go back to minimum using the value from this attribute.
+
+``max_freq_khz``
+ This attribute is used to set the maximum uncore frequency.
+
+``min_freq_khz``
+ This attribute is used to set the minimum uncore frequency.
+
+``current_freq_khz``
+ This attribute is used to get the current uncore frequency.
diff --git a/Documentation/admin-guide/pm/working-state.rst b/Documentation/admin-guide/pm/working-state.rst
index 5d2757e2de65..ee45887811ff 100644
--- a/Documentation/admin-guide/pm/working-state.rst
+++ b/Documentation/admin-guide/pm/working-state.rst
@@ -15,3 +15,4 @@ Working-State Power Management
cpufreq_drivers
intel_epb
intel-speed-select
+ intel_uncore_frequency_scaling