linux-kernel - Re: [PATCH v11 09/11] Documentation: introduce amd pstate active mode kernel command line options

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Message-ID: <dce77829-4ee7-6460-da36-116d165286b1@amd.com>
Date:   Thu, 19 Jan 2023 11:02:43 +0530
From:   Wyes Karny <wyes.karny@....com>
To:     Perry Yuan <perry.yuan@....com>
Cc:     Deepak.Sharma@....com, Nathan.Fontenot@....com,
        Alexander.Deucher@....com, Shimmer.Huang@....com,
        Xiaojian.Du@....com, Li.Meng@....com, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, rafael.j.wysocki@...el.com,
        Mario.Limonciello@....com, ray.huang@....com,
        viresh.kumar@...aro.org
Subject: Re: [PATCH v11 09/11] Documentation: introduce amd pstate active mode
 kernel command line options



On 1/18/2023 1:22 PM, Perry Yuan wrote:
> AMD Pstate driver support another firmware based autonomous mode
> with "amd_pstate=active" added to the kernel command line.
> In autonomous mode SMU firmware decides frequencies at runtime
> based on workload utilization, usage in other IPs, infrastructure
> limits such as power, thermals and so on.
> 
> Acked-by: Huang Rui <ray.huang@....com>
> Reviewed-by: Mario Limonciello <mario.limonciello@....com>
> Tested-by: Wyes Karny <wyes.karny@....com>
> Signed-off-by: Perry Yuan <perry.yuan@....com>
Reviewed-by: Wyes Karny <wyes.karny@....com>

> ---
>  Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 6cfa6e3996cf..e3618dfdb36a 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -7020,3 +7020,10 @@
>  			  management firmware translates the requests into actual
>  			  hardware states (core frequency, data fabric and memory
>  			  clocks etc.)
> +			active
> +			  Use amd_pstate_epp driver instance as the scaling driver,
> +			  driver provides a hint to the hardware if software wants
> +			  to bias toward performance (0x0) or energy efficiency (0xff)
> +			  to the CPPC firmware. then CPPC power algorithm will
> +			  calculate the runtime workload and adjust the realtime cores
> +			  frequency.

-- 
Thanks & Regards,
Wyes