Re: [PATCH v14 4/5] Documentation: cpufreq: amd-pstate: update doc for Per CPU boost control method

Gautham R.Shenoy
2024-06-25T12:04:02Z

Mario Limonciello <mario.limonciello@amd.com> writes:

> From: Perry Yuan <perry.yuan@amd.com>
>
> 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>
> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

LGTM

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>

> ---
> Documentation/admin-guide/pm/amd-pstate.rst | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index f5ee81419a93..d0324d44f548 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -281,6 +281,22 @@ 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.
> +
> Other performance and frequency values can be read back from
> ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
>
> --
> 2.43.0