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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Tue, 8 Dec 2020 18:24:19 +0100
Message-ID: <CAJZ5v0g0WkzJkO8GAa_XrNFNmzRw6aVeS+DLLyTVRXnp9mq65w@mail.gmail.com>
Subject: Re: [RESEND PATCH V3] PM / EM: Micro optimization in em_cpu_energy
To:     Pavankumar Kondeti <pkondeti@codeaurora.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Lukasz Luba <lukasz.luba@arm.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Quentin Perret <qperret@google.com>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>
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On Sat, Nov 28, 2020 at 3:21 AM Pavankumar Kondeti
<pkondeti@codeaurora.org> wrote:
>
> When the sum of the utilization of CPUs in a power domain is zero,
> return the energy as 0 without doing any computations.
>
> Acked-by: Quentin Perret <qperret@google.com>
> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
> ---
>  include/linux/energy_model.h | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
> index b67a51c..8810f1f 100644
> --- a/include/linux/energy_model.h
> +++ b/include/linux/energy_model.h
> @@ -103,6 +103,9 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd,
>         struct em_perf_state *ps;
>         int i, cpu;
>
> +       if (!sum_util)
> +               return 0;
> +
>         /*
>          * In order to predict the performance state, map the utilization of
>          * the most utilized CPU of the performance domain to a requested
> --

Applied as 5.11 material, thanks!