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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>,
	Perry Yuan <Perry.Yuan@amd.com>
Subject: [PATCH v4 2/9] Documentation: amd-pstate: add EPP profiles introduction
Date: Fri, 11 Nov 2022 01:58:40 +0800	[thread overview]
Message-ID: <20221110175847.3098728-3-Perry.Yuan@amd.com> (raw)
In-Reply-To: <20221110175847.3098728-1-Perry.Yuan@amd.com>

The patch add AMD pstate EPP feature introduction and what EPP
preference supported for AMD processors.

User can get supported list from
energy_performance_available_preferences attribute file, or update
current profile to energy_performance_preference file

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"

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 8f3d30c5a0d8..e7488891b12f 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:[~2022-11-10 17:59 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-10 17:58 [PATCH v4 0/9] Implement AMD Pstate EPP Driver Perry Yuan
2022-11-10 17:58 ` [PATCH v4 1/9] ACPI: CPPC: Add AMD pstate energy performance preference cppc control Perry Yuan
2022-11-10 17:58 ` Perry Yuan [this message]
2022-11-10 17:58 ` [PATCH v4 3/9] cpufreq: amd-pstate: change amd-pstate driver to be built-in type Perry Yuan
2022-11-14 22:46   ` Limonciello, Mario
2022-11-15  2:02     ` Yuan, Perry
2022-11-10 17:58 ` [PATCH v4 4/9] cpufreq: amd_pstate: implement Pstate EPP support for the AMD processors Perry Yuan
2022-11-14 22:40   ` Limonciello, Mario
2022-11-30 17:12     ` Yuan, Perry
2022-12-02  8:18     ` Yuan, Perry
2022-11-17 14:02   ` Wyes Karny
2022-11-18  3:54     ` Yuan, Perry
2022-11-10 17:58 ` [PATCH v4 5/9] cpufreq: amd_pstate: implement amd pstate cpu online and offline callback Perry Yuan
2022-11-10 17:58 ` [PATCH v4 6/9] cpufreq: amd-pstate: implement suspend and resume callbacks Perry Yuan
2022-11-10 17:58 ` [PATCH v4 7/9] cpufreq: amd-pstate: add frequency dynamic boost sysfs control Perry Yuan
2022-11-14 22:30   ` Limonciello, Mario
2022-11-30 17:13     ` Yuan, Perry
2022-11-10 17:58 ` [PATCH v4 8/9] cpufreq: amd_pstate: add driver working mode status sysfs entry Perry Yuan
2022-11-14 22:30   ` Limonciello, Mario
2022-11-30 17:13     ` Yuan, Perry
2022-11-10 17:58 ` [PATCH v4 9/9] Documentation: amd-pstate: add amd pstate driver mode introduction Perry Yuan
2022-11-14 22:29   ` Limonciello, Mario
2022-12-02  8:20     ` Yuan, Perry

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