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From: Perry Yuan <Perry.Yuan@amd.com>
To: <rafael.j.wysocki@intel.com>, <ray.huang@amd.com>,
	<viresh.kumar@linaro.org>
Cc: <Deepak.Sharma@amd.com>, <Mario.Limonciello@amd.com>,
	<Nathan.Fontenot@amd.com>, <Alexander.Deucher@amd.com>,
	<Jinzhou.Su@amd.com>, <Shimmer.Huang@amd.com>,
	<Xiaojian.Du@amd.com>, <Li.Meng@amd.com>,
	<linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	Perry Yuan <Perry.Yuan@amd.com>
Subject: [PATCH 3/7] Documentation: amd-pstate: add EPP profiles introduction
Date: Sat, 10 Sep 2022 00:45:30 +0800	[thread overview]
Message-ID: <20220909164534.71864-4-Perry.Yuan@amd.com> (raw)
In-Reply-To: <20220909164534.71864-1-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 83b58eb4ab4d..d0f0e115013b 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -261,6 +261,25 @@ lowest non-linear performance in `AMD CPPC Performance Capability
 <perf_cap_>`_.)
 This attribute is read-only.
 
+``energy_performance_available_preferences``
+
+All the supported EPP preference could be selected, List of the strings that
+can be set to the ``energy_performance_preference`` attribute
+those different profiles represent different energy vs efficiency hints provided
+to low-level firmware
+however, the ``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:[~2022-09-09 16:47 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-09 16:45 [PATCH 0/7] Implement AMD Pstate EPP Driver Perry Yuan
2022-09-09 16:45 ` [PATCH 1/7] ACPI: CPPC: Add AMD pstate energy performance preference cppc control Perry Yuan
2022-09-09 16:45 ` [PATCH 2/7] cpufreq: amd_pstate: add module parameter to load amd pstate EPP driver Perry Yuan
2022-09-09 18:49   ` Limonciello, Mario
2022-09-13 15:14     ` Yuan, Perry
2022-09-25 16:58     ` Yuan, Perry
2022-09-09 16:45 ` Perry Yuan [this message]
2022-09-09 16:45 ` [PATCH 4/7] cpufreq: amd_pstate: add AMD pstate EPP support for shared memory type processor Perry Yuan
2022-09-09 18:52   ` Limonciello, Mario
2022-09-13 15:20     ` Yuan, Perry
2022-09-25 17:01     ` Yuan, Perry
2022-09-15 16:24   ` Nathan Fontenot
2022-09-25 12:23     ` Yuan, Perry
2022-09-29 14:08       ` Nathan Fontenot
2022-09-09 16:45 ` [PATCH 5/7] cpufreq: amd_pstate: add AMD Pstate EPP support for the MSR based processors Perry Yuan
2022-09-15 18:58   ` Nathan Fontenot
2022-09-25 17:12     ` Yuan, Perry
2022-09-09 16:45 ` [PATCH 6/7] cpufreq: amd_pstate: implement amd pstate cpu online and offline callback Perry Yuan
2022-09-09 19:02   ` Limonciello, Mario
2022-09-15 19:03   ` Nathan Fontenot
2022-09-09 16:45 ` [PATCH 7/7] cpufreq: amd-pstate: implement suspend and resume callbacks Perry Yuan
2022-09-09 19:00   ` Limonciello, Mario

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