linux-kernel - Re: [PATCH 1/2] PM: EM: Fix incorrect description of the cost field in struct em_perf

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Message-ID: <d5ee5e5b-d636-47c7-83e6-b58cab9f4d6e@arm.com>
Date: Tue, 30 Dec 2025 09:35:49 +0000
From: Lukasz Luba <lukasz.luba@....com>
To: Yaxiong Tian <tianyaxiong@...inos.cn>
Cc: linux-pm@...r.kernel.org, lenb@...nel.org, linux-kernel@...r.kernel.org,
 pavel@...nel.org, rafael@...nel.org
Subject: Re: [PATCH 1/2] PM: EM: Fix incorrect description of the cost field
 in struct em_perf_state



On 12/30/25 06:15, Yaxiong Tian wrote:
> Due to commit 1b600da51073 ("PM: EM: Optimize em_cpu_energy() and remove
> division"), the logic for energy consumption calculation has been modified.
> The actual calculation of cost is 10 * power * max_frequency / frequency
> instead of power * max_frequency / frequency.
> 
> Therefore, the comment for cost has been updated to reflect the correct
> content.
> 
> Signed-off-by: Yaxiong Tian <tianyaxiong@...inos.cn>
> ---
>   include/linux/energy_model.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
> index 43aa6153dc57..e7497f804644 100644
> --- a/include/linux/energy_model.h
> +++ b/include/linux/energy_model.h
> @@ -18,7 +18,7 @@
>    * @power:	The power consumed at this level (by 1 CPU or by a registered
>    *		device). It can be a total power: static and dynamic.
>    * @cost:	The cost coefficient associated with this level, used during
> - *		energy calculation. Equal to: power * max_frequency / frequency
> + *		energy calculation. Equal to: 10 * power * max_frequency / frequency
>    * @flags:	see "em_perf_state flags" description below.
>    */
>   struct em_perf_state {

Good catch, thank you!

Reviewed-by: Lukasz Luba <lukasz.luba@....com>