From: Wyes Karny <wyes.karny@amd.com>
To: Rafael J Wysocki <rafael@kernel.org>,
Huang Rui <ray.huang@amd.com>, Jonathan Corbet <corbet@lwn.net>,
Viresh Kumar <viresh.kumar@linaro.org>,
<Mario.Limonciello@amd.com>, <Perry.Yuan@amd.com>
Cc: <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-pm@vger.kernel.org>, Bagas Sanjaya <bagasdotme@gmail.com>,
<santosh.shukla@amd.com>, Len Brown <lenb@kernel.org>,
Robert Moore <robert.moore@intel.com>,
Borislav Petkov <bp@alien8.de>,
Ananth Narayan <ananth.narayan@amd.com>, <gautham.shenoy@amd.com>,
Tor Vic <torvic9@mailbox.org>, Wyes Karny <wyes.karny@amd.com>,
Mario Limonciello <mario.limonciello@amd.com>
Subject: [PATCH v5 6/6] Documentation: amd_pstate: Update amd_pstate status sysfs for guided
Date: Wed, 1 Feb 2023 06:58:23 +0000 [thread overview]
Message-ID: <20230201065823.189828-7-wyes.karny@amd.com> (raw)
In-Reply-To: <20230201065823.189828-1-wyes.karny@amd.com>
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 | 34 ++++++++++++++++-----
1 file changed, 27 insertions(+), 7 deletions(-)
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 5304adf2fc2f..17fafe5d6625 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.
@@ -368,6 +385,9 @@ control its functionality at the system level. They are located in the
to the operation mode represented by that string - or to be
unregistered in the "disable" case.
+Note: If someone tries to change the state to same state, which is currently
+active in the driver, then this will return -EBUSY error.
+
``cpupower`` tool support for ``amd-pstate``
===============================================
--
2.34.1
next prev parent reply other threads:[~2023-02-01 7:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 6:58 [PATCH v5 0/6] amd_pstate: Add guided autonomous mode support Wyes Karny
2023-02-01 6:58 ` [PATCH v5 1/6] acpi: cppc: Add min and max perf reg writing support Wyes Karny
2023-02-01 6:58 ` [PATCH v5 2/6] acpi: cppc: Add auto select register read/write support Wyes Karny
2023-02-01 6:58 ` [PATCH v5 3/6] cpufreq: amd_pstate: Add guided autonomous mode Wyes Karny
2023-02-01 6:58 ` [PATCH v5 4/6] Documentation: amd_pstate: Move amd_pstate param to alphabetical order Wyes Karny
2023-02-01 6:58 ` [PATCH v5 5/6] cpufreq: amd_pstate: Add guided mode control support via sysfs Wyes Karny
2023-02-01 6:58 ` Wyes Karny [this message]
2023-02-01 18:35 ` [PATCH v5 0/6] amd_pstate: Add guided autonomous mode support Tor Vic
2023-02-02 4:44 ` Wyes Karny
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