linux-kernel - Re: [PATCH] cpufreq: intel_pstate: Directly use stored ratios for max frequencies

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Date: Mon, 22 Jan 2024 04:45:22 -0800
From: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>, viresh.kumar@...aro.org,
 linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: intel_pstate: Directly use stored ratios for max
 frequencies


On 1/22/24 03:46, Rafael J. Wysocki wrote:
> On Mon, Jan 22, 2024 at 12:35 PM srinivas pandruvada
> <srinivas.pandruvada@...ux.intel.com> wrote:
>> On Mon, 2024-01-22 at 11:53 +0100, Rafael J. Wysocki wrote:
>>> On Thursday, January 18, 2024 1:05:13 PM CET Srinivas Pandruvada
>>> wrote:
>>>> Avoid unnecessary calculation for converting frequency to
>>>> performance
>>>> ratio by using a scaling factor for the maximum non turbo and turbo
>> [...]
>>
>>> ---
>>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>>> Subject: [PATCH v1] cpufreq: intel_pstate: Refine computation of P-
>>> state for given frequency
>>>
>>> On systems using HWP, if a given frequency is equal to the maximum
>>> turbo
>>> frequency or the maximum non-turbo frequency, the HWP performance
>>> level
>>> corresponding to it is already known and can be used directly without
>>> any computation.
>>>
>>> Accordingly, adjust the code to use the known HWP performance levels
>>> in
>>> the cases mentioned above.
>>>
>>> This also helps to avoid limiting CPU capacity artificially in some
>>> cases when the BIOS produces the HWP_CAP numbers using a different
>>> E-core-to-P-core performance scaling factor than expected by the
>>> kernel.
>>>
>>> Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known
>>> scaling factor for P-cores")
>>> Cc: 6.1+ <stable@...r.kernel.org> # 6.1+
>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>>> ---
>> Tested on the system which showed the issue, this patch work fine.
> So I'm going to add a Tested-by from you to it or please let me know
> if you don't want me to do so.

You can add.

Thanks,

Srinivas