[PATCH v2 6/6] Documentation: amd_pstate: Update amd_pstate status sysfs for guided

Wyes Karny
2023-01-13T05:27:04Z

Update amd_pstate status sysfs for guided mode.

Signed-off-by: Wyes Karny <wyes.karny@amd.com>
---
Documentation/admin-guide/pm/amd-pstate.rst | 29 ++++++++++++++++-----
1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 55396981266a..92fa22e45a2b 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -303,13 +303,16 @@ 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, guided
+autonomous (guided) mode and non-autonomous (passive) 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 requested performance,
+Maximum requested performance 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 +341,15 @@ 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 +370,9 @@ 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