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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-04-14 17:18:07 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-04-14 17:18:07 +0200
commit684952212ca639bce124e673f9f644a09895359c (patch)
treed69b9291f10610ad4c71393ed71fabed91f07f70 /Documentation
parentamd-pstate: Fix amd_pstate mode switch (diff)
parentcpufreq: amd-pstate: Make varaiable mode_state_machine static (diff)
downloadlinux-684952212ca639bce124e673f9f644a09895359c.tar.xz
linux-684952212ca639bce124e673f9f644a09895359c.zip
Merge back cpufreq changes for 6.4-rc1.
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt40
-rw-r--r--Documentation/admin-guide/pm/amd-pstate.rst31
2 files changed, 47 insertions, 24 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6221a1d057dd..1e5fe4891dd7 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -339,6 +339,29 @@
This mode requires kvm-amd.avic=1.
(Default when IOMMU HW support is present.)
+ amd_pstate= [X86]
+ disable
+ Do not enable amd_pstate as the default
+ scaling driver for the supported processors
+ passive
+ Use amd_pstate with passive mode as a scaling driver.
+ In this mode autonomous selection is disabled.
+ Driver requests a desired performance level and platform
+ tries to match the same performance level if it is
+ satisfied by guaranteed performance level.
+ 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.
+ guided
+ Activate guided autonomous mode. Driver requests minimum and
+ maximum performance level and the platform autonomously
+ selects a performance level in this range and appropriate
+ to the current workload.
+
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
Format: <a>,<b>
@@ -7059,20 +7082,3 @@
xmon commands.
off xmon is disabled.
- amd_pstate= [X86]
- disable
- Do not enable amd_pstate as the default
- scaling driver for the supported processors
- passive
- Use amd_pstate as a scaling driver, driver requests a
- desired performance on this abstract scale and the power
- 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 6e5298b521b1..1cf40f69278c 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -303,13 +303,18 @@ efficiency frequency management method on AMD processors.
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.
+``amd_pstate`` CPPC has 3 operation modes: autonomous (active) mode,
+non-autonomous (passive) mode and guided autonomous (guided) mode.
+Active/passive/guided mode can be chosen by different kernel parameters.
+
+- In autonomous mode, platform ignores the desired performance level request
+ and takes into account only the values set to the minimum, maximum and energy
+ performance preference registers.
+- In non-autonomous mode, platform gets desired performance level
+ from OS directly through Desired Performance Register.
+- In guided-autonomous mode, platform sets operating performance level
+ autonomously according to the current workload and within the limits set by
+ OS through min and max performance registers.
Active Mode
------------
@@ -338,6 +343,15 @@ to the Performance Reduction Tolerance register. Above the nominal performance l
processor must provide at least nominal performance requested and go higher if current
operating conditions allow.
+Guided Mode
+-----------
+
+``amd_pstate=guided``
+
+If ``amd_pstate=guided`` is passed to kernel command line option then this mode
+is activated. In this mode, driver requests minimum and maximum performance
+level and the platform autonomously selects a performance level in this range
+and appropriate to the current workload.
User Space Interface in ``sysfs`` - General
===========================================
@@ -358,6 +372,9 @@ control its functionality at the system level. They are located in the
"passive"
The driver is functional and in the ``passive mode``
+ "guided"
+ The driver is functional and in the ``guided mode``
+
"disable"
The driver is unregistered and not functional now.