linux-kernel - [PATCH v13 8/9] Documentation: cpufreq: amd-pstate: introduce the new cpu boost control method

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Message-ID: <9725dfcbb8848d68ce5c8c099cd3c6805bebf20b.1718988436.git.perry.yuan@amd.com>
Date: Sat, 22 Jun 2024 00:51:03 +0800
From: Perry Yuan <perry.yuan@....com>
To: <rafael.j.wysocki@...el.com>, <Mario.Limonciello@....com>,
	<viresh.kumar@...aro.org>, <gautham.shenoy@....com>
CC: <Alexander.Deucher@....com>, <Xinmei.Huang@....com>,
	<Xiaojian.Du@....com>, <Li.Meng@....com>, <linux-pm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH v13 8/9] Documentation: cpufreq: amd-pstate: introduce the new cpu boost control method

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

Introduce AMD CPU frequency boosting control sysfs entry which used for
switching boost on and boost off.

If core performance boost is disabled while a core is in a boosted P-state,
the core automatically transitions to the highest performance non-boosted P-state
The highest perf and frequency will be limited by the setting value.

Signed-off-by: Perry Yuan <Perry.Yuan@....com>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>
---
 Documentation/admin-guide/pm/amd-pstate.rst | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index f5ee81419a93..dc1b10d7dd09 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -440,6 +440,23 @@ control its functionality at the system level.  They are located in the
         This attribute is read-only to check the state of preferred core set
         by the kernel parameter.
 
+``cpb_boost``
+        Specifies whether core performance boost is requested to be enabled or disabled
+        If core performance boost is disabled while a core is in a boosted P-state, the
+        core automatically transitions to the highest performance non-boosted P-state.
+        AMD Core Performance Boost(CPB) is controlled by this attribute file which allows
+        user to change all cores frequency boosting state. It supports all amd-pstate modes.
+
+        States of the driver "/sys/devices/system/cpu/amd_pstate/cpb_boost"
+        "disabled" Core Performance Boosting Disabled.
+        "enabled"  Core Performance Boosting Enabled.
+
+        To enable core performance boost:
+          # echo "enabled" > /sys/devices/system/cpu/amd_pstate/cpb_boost
+
+        To disable core performance boost:
+          # echo "disabled" > /sys/devices/system/cpu/amd_pstate/cpb_boost
+
 ``cpupower`` tool support for ``amd-pstate``
 ===============================================
 
-- 
2.34.1