[PATCH v6 6/6] Documentation: amd_pstate: Update amd_pstate status sysfs for guided

Wyes Karny
2023-02-06T17:26:29Z

Update amd_pstate status sysfs for guided mode.

Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
---
Documentation/admin-guide/pm/amd-pstate.rst | 31 ++++++++++++++++-----
1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 5304adf2fc2f..95d2d0a803fe 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``
=================================
@@ -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.

--
2.34.1