linux-kernel - Re: [PATCH] cpufreq: schedutil: Move max CPU capacity to sugov

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Date:   Tue, 12 Jul 2022 14:11:37 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Lukasz Luba <lukasz.luba@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        rafael@...nel.org, dietmar.eggemann@....com,
        vincent.guittot@...aro.org
Subject: Re: [PATCH] cpufreq: schedutil: Move max CPU capacity to sugov_policy

On 11-07-22, 13:42, Lukasz Luba wrote:
> There is no need to keep the max CPU capacity in the per_cpu instance.
> Furthermore, there is no need to check and update that variable
> (sg_cpu->max) everytime in the frequency change request, which is part
> of hot path. Instead use struct sugov_policy to store that information.
> Initialize the max CPU capacity during the setup and start callback.
> We can do that since all CPUs in the same frequency domain have the same
> max capacity (capacity setup and thermal pressure are based on that).
> 
> Signed-off-by: Lukasz Luba <lukasz.luba@....com>
> ---
>  kernel/sched/cpufreq_schedutil.c | 30 +++++++++++++++---------------
>  1 file changed, 15 insertions(+), 15 deletions(-)

I tried to check all possible combinations on how this can break, but
couldn't find one. I had to check that as this code is there since
ages and none of us thought of it, which was surprising.

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh