Re: [PATCH v6 6/6] Documentation: amd_pstate: Update amd_pstate status sysfs for guided

Huang Rui
2023-02-16T06:17:58Z

On Tue, Feb 07, 2023 at 01:21:57AM +0800, Karny, Wyes wrote:
> Update amd_pstate status sysfs for guided mode.
>
> Signed-off-by: Wyes Karny <wyes.karny@amd.com>
> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

Acked-by: Huang Rui <ray.huang@amd.com>

> ---
> Documentation/admin-guide/pm/amd-pstate.rst | 31 ++++++++++++++++-----
> 1 file changed, 24 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index 5304adf2fc2f..95d2d0a803fe 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -303,13 +303,18 @@ efficiency frequency management method on AMD processors.
> AMD Pstate Driver Operation Modes
> =================================
>
> -``amd_pstate`` CPPC has two operation modes: CPPC Autonomous(active) mode and
> -CPPC non-autonomous(passive) mode.
> -active mode and passive mode can be chosen by different kernel parameters.
> -When in Autonomous mode, CPPC ignores requests done in the Desired Performance
> -Target register and takes into account only the values set to the Minimum requested
> -performance, Maximum requested performance, and Energy Performance Preference
> -registers. When Autonomous is disabled, it only considers the Desired Performance Target.
> +``amd_pstate`` CPPC has 3 operation modes: autonomous (active) mode,
> +non-autonomous (passive) mode and guided autonomous (guided) mode.
> +Active/passive/guided mode can be chosen by different kernel parameters.
> +
> +- In autonomous mode, platform ignores the desired performance level request
> + and takes into account only the values set to the minimum, maximum and energy
> + performance preference registers.
> +- In non-autonomous mode, platform gets desired performance level
> + from OS directly through Desired Performance Register.
> +- In guided-autonomous mode, platform sets operating performance level
> + autonomously according to the current workload and within the limits set by
> + OS through min and max performance registers.
>
> Active Mode
> ------------
> @@ -338,6 +343,15 @@ to the Performance Reduction Tolerance register. Above the nominal performance l
> processor must provide at least nominal performance requested and go higher if current
> operating conditions allow.
>
> +Guided Mode
> +-----------
> +
> +``amd_pstate=guided``
> +
> +If ``amd_pstate=guided`` is passed to kernel command line option then this mode
> +is activated. In this mode, driver requests minimum and maximum performance
> +level and the platform autonomously selects a performance level in this range
> +and appropriate to the current workload.
>
> User Space Interface in ``sysfs``
> =================================
> @@ -358,6 +372,9 @@ control its functionality at the system level. They are located in the
> "passive"
> The driver is functional and in the ``passive mode``
>
> + "guided"
> + The driver is functional and in the ``guided mode``
> +
> "disable"
> The driver is unregistered and not functional now.
>
> --
> 2.34.1
>