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From: Perry Yuan <perry.yuan@amd.com>
To: <rafael.j.wysocki@intel.com>, <Mario.Limonciello@amd.com>,
	<ray.huang@amd.com>, <viresh.kumar@linaro.org>
Cc: <Deepak.Sharma@amd.com>, <Nathan.Fontenot@amd.com>,
	<Alexander.Deucher@amd.com>, <Shimmer.Huang@amd.com>,
	<Xiaojian.Du@amd.com>, <Li.Meng@amd.com>, <wyes.karny@amd.com>,
	<linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v10 02/12] Documentation: amd-pstate: add EPP profiles introduction
Date: Fri, 6 Jan 2023 14:14:10 +0800	[thread overview]
Message-ID: <20230106061420.95715-3-perry.yuan@amd.com> (raw)
In-Reply-To: <20230106061420.95715-1-perry.yuan@amd.com>

From: Perry Yuan <Perry.Yuan@amd.com>

The amd-pstate driver supports a feature called energy performance
preference (EPP). Add information to the documentation to explain
how users can interact with the sysfs files for this feature.

1) See all EPP profiles
$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_preferences
default performance balance_performance balance_power power

2) Check current EPP profile
$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
performance

3) Set new EPP profile
$ sudo bash -c "echo power > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference"

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
 Documentation/admin-guide/pm/amd-pstate.rst | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 06e23538f79c..33ab8ec8fc2f 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC Performance Capability
 <perf_cap_>`_.)
 This attribute is read-only.
 
+``energy_performance_available_preferences``
+
+A list of all the supported EPP preferences that could be used for
+``energy_performance_preference`` on this system.
+These profiles represent different hints that are provided
+to the low-level firmware about the user's desired energy vs efficiency
+tradeoff.  ``default`` represents the epp value is set by platform
+firmware. This attribute is read-only.
+
+``energy_performance_preference``
+
+The current energy performance preference can be read from this attribute.
+and user can change current preference according to energy or performance needs
+Please get all support profiles list from
+``energy_performance_available_preferences`` attribute, all the profiles are
+integer values defined between 0 to 255 when EPP feature is enabled by platform
+firmware, if EPP feature is disabled, driver will ignore the written value
+This attribute is read-write.
+
 Other performance and frequency values can be read back from
 ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
 
-- 
2.34.1


  parent reply	other threads:[~2023-01-06  6:15 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-06  6:14 [PATCH v10 00/12] Implement AMD Pstate EPP Driver Perry Yuan
2023-01-06  6:14 ` [PATCH v10 01/12] ACPI: CPPC: Add AMD pstate energy performance preference cppc control Perry Yuan
2023-01-17 11:10   ` Huang Rui
2023-01-06  6:14 ` Perry Yuan [this message]
2023-01-17 11:45   ` [PATCH v10 02/12] Documentation: amd-pstate: add EPP profiles introduction Huang Rui
2023-01-06  6:14 ` [PATCH v10 03/12] cpufreq: intel_pstate: use common macro definition for Energy Preference Performance(EPP) Perry Yuan
2023-01-06  9:38   ` kernel test robot
2023-01-06 10:19   ` kernel test robot
2023-01-06  6:14 ` [PATCH v10 04/12] cpufreq: amd-pstate: optimize driver working mode selection in amd_pstate_param() Perry Yuan
2023-01-17 11:57   ` Huang Rui
2023-01-06  6:14 ` [PATCH v10 05/12] cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors Perry Yuan
2023-01-06 11:19   ` Wyes Karny
2023-01-10 15:21     ` Yuan, Perry
2023-01-10 18:15   ` kernel test robot
2023-01-17 13:34   ` Huang Rui
2023-01-06  6:14 ` [PATCH v10 06/12] cpufreq: amd-pstate: implement amd pstate cpu online and offline callback Perry Yuan
2023-01-06  6:14 ` [PATCH v10 07/12] cpufreq: amd-pstate: implement suspend and resume callbacks Perry Yuan
2023-01-06  6:14 ` [PATCH v10 08/12] cpufreq: amd-pstate: add driver working mode switch support Perry Yuan
2023-01-17 13:56   ` Huang Rui
2023-01-18  6:34     ` Wyes Karny
2023-01-18  7:27       ` Yuan, Perry
2023-01-06  6:14 ` [PATCH v10 09/12] Documentation: amd-pstate: add amd pstate driver mode introduction Perry Yuan
2023-01-06  6:14 ` [PATCH v10 10/12] Documentation: introduce amd pstate active mode kernel command line options Perry Yuan
2023-01-06  6:14 ` [PATCH v10 11/12] cpufreq: amd-pstate: convert sprintf with sysfs_emit() Perry Yuan
2023-01-06  6:14 ` [PATCH v10 12/12] Documentation: amd-pstate: introduce new global sysfs attributes Perry Yuan
2023-01-17 14:11   ` Huang Rui
2023-01-10 18:00 ` [PATCH v10 00/12] Implement AMD Pstate EPP Driver Wyes Karny
2023-01-17 14:03 ` Huang Rui

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