linux-kernel - Re: [PATCH v1 5/5] PM / devfreq: tegra30: Make CPUFreq notifier to take into account boosting

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Date:   Wed, 1 Apr 2020 08:29:31 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Dmitry Osipenko <digetx@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     linux-clk@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 5/5] PM / devfreq: tegra30: Make CPUFreq notifier to
 take into account boosting

Hi Dmitry,

On 3/31/20 8:16 AM, Dmitry Osipenko wrote:
> MCCPU frequency boosting needs to be taken into account in order to avoid
> scheduling of unnecessary devfreq updates.

"in order to avoid scheduling of unnecessary devfreq updates."
I don't understand the correct meaning of following description.
Could you explain it more detailed?

> 
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> ---
>  drivers/devfreq/tegra30-devfreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
> index 34f6291e880c..3b57aac9894c 100644
> --- a/drivers/devfreq/tegra30-devfreq.c
> +++ b/drivers/devfreq/tegra30-devfreq.c
> @@ -420,7 +420,7 @@ tegra_actmon_cpufreq_contribution(struct tegra_devfreq *tegra,
>  
>  	static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
>  
> -	if (dev_freq >= static_cpu_emc_freq)
> +	if (dev_freq + actmon_dev->boost_freq >= static_cpu_emc_freq)
>  		return 0;
>  
>  	return static_cpu_emc_freq;
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics