linux-kernel - Re: [PATCH 2/2] thermal: cpufreq_cooling: Reuse effective_cpu

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Message-ID: <20200722091338.syymxwgk6znnasvt@vireshk-mac-ubuntu>
Date:   Wed, 22 Jul 2020 14:43:38 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Quentin Perret <qperret@...gle.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Daniel Kachhap <amit.kachhap@...il.com>,
        Javi Merino <javi.merino@...nel.org>,
        Amit Kucheria <amit.kucheria@...durent.com>,
        linux-kernel@...r.kernel.org, Rafael Wysocki <rjw@...ysocki.net>,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/2] thermal: cpufreq_cooling: Reuse effective_cpu_util()

On 17-07-20, 11:43, Quentin Perret wrote:
> On Friday 17 Jul 2020 at 11:33:05 (+0100), Quentin Perret wrote:
> > On Friday 17 Jul 2020 at 11:14:38 (+0100), Quentin Perret wrote:
> > > On Tuesday 14 Jul 2020 at 12:06:53 (+0530), Viresh Kumar wrote:
> > > >  /**
> > > > - * get_load() - get load for a cpu since last updated
> > > > + * get_load() - get current load for a cpu
> > > >   * @cpufreq_cdev:	&struct cpufreq_cooling_device for this cpu
> > > >   * @cpu:	cpu number
> > > > - * @cpu_idx:	index of the cpu in time_in_idle*
> > > > + * @cpu_idx:	index of the cpu
> > > >   *
> > > > - * Return: The average load of cpu @cpu in percentage since this
> > > > - * function was last called.
> > > > + * Return: The current load of cpu @cpu in percentage.
> > > >   */
> > > >  static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
> > > >  		    int cpu_idx)
> > > >  {
> > > > -	u32 load;
> > > > -	u64 now, now_idle, delta_time, delta_idle;
> > > > -	struct time_in_idle *idle_time = &cpufreq_cdev->idle_time[cpu_idx];
> > > > -
> > > > -	now_idle = get_cpu_idle_time(cpu, &now, 0);
> > > > -	delta_idle = now_idle - idle_time->time;
> > > > -	delta_time = now - idle_time->timestamp;
> > > > +	unsigned long util = cpu_util_cfs(cpu_rq(cpu));
> > > > +	unsigned long max = arch_scale_cpu_capacity(cpu);
> > > 
> > > Should we subtract the thermal PELT signal from max?

Makes sense to me, but I am not really good with this util and load
stuff and so would leave that to you guys to decide :)

-- 
viresh