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[v11,9/9] Documentation: cpufreq: amd-pstate: update doc for Per CPU boost control method

Message ID f0c47cba673261c7d868d5236d3ffb15ae092e74.1718262992.git.perry.yuan@amd.com
State Superseded
Headers show
Series AMD Pstate Driver Core Performance Boost | expand

Commit Message

Yuan, Perry June 13, 2024, 7:25 a.m. UTC
Updates the documentation in `amd-pstate.rst` to include information about the
per CPU boost control feature. Users can now enable or disable the Core Performance
Boost (CPB) feature on individual CPUs using the `boost` sysfs attribute.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 Documentation/admin-guide/pm/amd-pstate.rst | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Mario Limonciello June 13, 2024, 5:53 p.m. UTC | #1
On 6/13/2024 02:25, Perry Yuan wrote:
> Updates the documentation in `amd-pstate.rst` to include information about the
> per CPU boost control feature. Users can now enable or disable the Core Performance
> Boost (CPB) feature on individual CPUs using the `boost` sysfs attribute.
> 
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

> ---
>   Documentation/admin-guide/pm/amd-pstate.rst | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
> 
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index bcc0d9404c18..98e43c53c387 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -281,6 +281,26 @@ 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.
>   
> +``boost``
> +The `boost` sysfs attribute provides control over the CPU core
> +performance boost, allowing users to manage the maximum frequency limitation
> +of the CPU. This attribute can be used to enable or disable the boost feature
> +on individual CPUs.
> +
> +When the boost feature is enabled, the CPU can dynamically increase its frequency
> +beyond the base frequency, providing enhanced performance for demanding workloads.
> +On the other hand, disabling the boost feature restricts the CPU to operate at the
> +base frequency, which may be desirable in certain scenarios to prioritize power
> +efficiency or manage temperature.
> +
> +To manipulate the `boost` attribute, users can write a value of `0` to disable the
> +boost or `1` to enable it, for the respective CPU using the sysfs path
> +`/sys/devices/system/cpu/cpuX/cpufreq/boost`, where `X` represents the CPU number.
> +
> +It is important to note that modifying the global variable
> +`amd_pstate_global_params.cpb_boost` will override the individual CPU settings.
> +
> +
>   Other performance and frequency values can be read back from
>   ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
>
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Patch

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index bcc0d9404c18..98e43c53c387 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -281,6 +281,26 @@  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.
 
+``boost``
+The `boost` sysfs attribute provides control over the CPU core
+performance boost, allowing users to manage the maximum frequency limitation
+of the CPU. This attribute can be used to enable or disable the boost feature
+on individual CPUs.
+
+When the boost feature is enabled, the CPU can dynamically increase its frequency
+beyond the base frequency, providing enhanced performance for demanding workloads.
+On the other hand, disabling the boost feature restricts the CPU to operate at the
+base frequency, which may be desirable in certain scenarios to prioritize power
+efficiency or manage temperature.
+
+To manipulate the `boost` attribute, users can write a value of `0` to disable the
+boost or `1` to enable it, for the respective CPU using the sysfs path
+`/sys/devices/system/cpu/cpuX/cpufreq/boost`, where `X` represents the CPU number.
+
+It is important to note that modifying the global variable
+`amd_pstate_global_params.cpb_boost` will override the individual CPU settings.
+
+
 Other performance and frequency values can be read back from
 ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.