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From: Perry Yuan <>
To: <>, <>,
Cc: <>, <>,
	<>, <>,
	<>, <>, <>,
	<>, <>,
	Perry Yuan <>
Subject: [PATCH v2 5/9] Documentation: amd-pstate: add EPP profiles introduction
Date: Sun, 9 Oct 2022 15:10:29 +0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

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

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

Signed-off-by: Perry Yuan <>
 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
 This attribute is read-only.
+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.
+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`.

  parent reply	other threads:[~2022-10-09  7:11 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-09  7:10 [PATCH v2 0/9] Implement AMD Pstate EPP Driver Perry Yuan
2022-10-09  7:10 ` [PATCH v2 1/9] ACPI: CPPC: Add AMD pstate energy performance preference cppc control Perry Yuan
2022-10-09  7:10 ` [PATCH v2 2/9] cpufreq: amd_pstate: add module parameter to load amd pstate EPP driver Perry Yuan
2022-10-09  7:10 ` [PATCH v2 3/9] cpufreq: cpufreq: export cpufreq cpu release and acquire Perry Yuan
2022-10-09  7:10 ` [PATCH v2 4/9] x86/msr: Add the MSR definition for AMD CPPC boost state Perry Yuan
2022-10-09  7:10 ` Perry Yuan [this message]
2022-10-09  7:10 ` [PATCH v2 6/9] cpufreq: amd_pstate: add AMD pstate EPP support for shared memory type processor Perry Yuan
2022-10-09  7:10 ` [PATCH v2 7/9] cpufreq: amd_pstate: add AMD Pstate EPP support for the MSR based processors Perry Yuan
2022-10-09 11:26   ` kernel test robot
2022-10-09 11:26   ` kernel test robot
2022-10-09  7:10 ` [PATCH v2 8/9] cpufreq: amd_pstate: implement amd pstate cpu online and offline callback Perry Yuan
2022-10-09  7:10 ` [PATCH v2 9/9] cpufreq: amd-pstate: implement suspend and resume callbacks Perry Yuan

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