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From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Douglas RAILLARD <douglas.raillard@arm.com>,
	linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org, mingo@redhat.com, peterz@infradead.org,
	rjw@rjwysocki.net, viresh.kumar@linaro.org,
	juri.lelli@redhat.com, vincent.guittot@linaro.org,
	qperret@qperret.net, patrick.bellasi@matbug.net,
	dh.han@samsung.com
Subject: Re: [RFC PATCH v3 1/6] PM: Introduce em_pd_get_higher_freq()
Date: Thu, 17 Oct 2019 10:57:11 +0200
Message-ID: <62e34c1a-752d-d55d-1004-ddd586fa3f98@arm.com> (raw)
In-Reply-To: <20191011134500.235736-2-douglas.raillard@arm.com>

On 11/10/2019 15:44, Douglas RAILLARD wrote:

[...]

> diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
> index d249b88a4d5a..dd6a35f099ea 100644
> --- a/include/linux/energy_model.h
> +++ b/include/linux/energy_model.h
> @@ -159,6 +159,53 @@ static inline int em_pd_nr_cap_states(struct em_perf_domain *pd)
>  	return pd->nr_cap_states;
>  }
>  
> +#define EM_COST_MARGIN_SCALE 1024U
> +
> +/**
> + * em_pd_get_higher_freq() - Get the highest frequency that does not exceed the
> + * given cost margin compared to min_freq
> + * @pd		: performance domain for which this must be done
> + * @min_freq	: minimum frequency to return
> + * @cost_margin	: allowed margin compared to min_freq, on the
> + *		  EM_COST_MARGIN_SCALE scale.
> + *
> + * Return: the chosen frequency, guaranteed to be at least as high as min_freq.
> + */
> +static inline unsigned long em_pd_get_higher_freq(struct em_perf_domain *pd,
> +	unsigned long min_freq, unsigned long cost_margin)
> +{
> +	unsigned long max_cost = 0;
> +	struct em_cap_state *cs;
> +	int i;
> +
> +	if (!pd)
> +		return min_freq;
> +
> +	/* Compute the maximum allowed cost */
> +	for (i = 0; i < pd->nr_cap_states; i++) {
> +		cs = &pd->table[i];
> +		if (cs->frequency >= min_freq) {
> +			max_cost = cs->cost +
> +				(cs->cost * cost_margin) / EM_COST_MARGIN_SCALE;
> +			break;
> +		}
> +	}
> +
> +	/* Find the highest frequency that will not exceed the cost margin */
> +	for (i = pd->nr_cap_states-1; i >= 0; i--) {
> +		cs = &pd->table[i];
> +		if (cs->cost <= max_cost)
> +			return cs->frequency;
> +	}
> +
> +	/*
> +	 * We should normally never reach here, unless min_freq was higher than
> +	 * the highest available frequency, which is not expected to happen.
> +	 */
> +	return min_freq;
> +}
> +
> +

Why two blank lines?

>  #else

Doesn't apply cleanly on v5.4-rc3. There seems to be a line missing?

27871f7a8a341 (Quentin Perret    2018-12-03 09:56:16 +0000 163) struct
em_perf_domain {};

[...]

  reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11 13:44 [RFC PATCH v3 0/6] sched/cpufreq: Make schedutil energy aware Douglas RAILLARD
2019-10-11 13:44 ` [RFC PATCH v3 1/6] PM: Introduce em_pd_get_higher_freq() Douglas RAILLARD
2019-10-17  8:57   ` Dietmar Eggemann [this message]
2019-10-17  9:58   ` Dietmar Eggemann
2019-10-17 11:09     ` Douglas Raillard
2019-10-11 13:44 ` [RFC PATCH v3 2/6] sched/cpufreq: Attach perf domain to sugov policy Douglas RAILLARD
2019-10-17  8:57   ` Dietmar Eggemann
2019-10-17 10:22     ` Douglas Raillard
2019-10-11 13:44 ` [RFC PATCH v3 3/6] sched/cpufreq: Hook em_pd_get_higher_power() into get_next_freq() Douglas RAILLARD
2019-10-11 13:44 ` [RFC PATCH v3 4/6] sched/cpufreq: Introduce sugov_cpu_ramp_boost Douglas RAILLARD
2019-10-14 14:33   ` Peter Zijlstra
2019-10-14 15:32     ` Douglas Raillard
2019-10-17  8:57   ` Dietmar Eggemann
2019-10-17 11:19     ` Douglas Raillard
2019-10-11 13:44 ` [RFC PATCH v3 5/6] sched/cpufreq: Boost schedutil frequency ramp up Douglas RAILLARD
2019-10-17  9:21   ` Dietmar Eggemann
2019-10-11 13:45 ` [RFC PATCH v3 6/6] sched/cpufreq: Add schedutil_em_tp tracepoint Douglas RAILLARD
2019-10-14 14:53 ` [RFC PATCH v3 0/6] sched/cpufreq: Make schedutil energy aware Peter Zijlstra
2019-10-14 15:50   ` Douglas Raillard
2019-10-17  9:50     ` Peter Zijlstra
2019-10-17 11:11       ` Quentin Perret
2019-10-17 14:11         ` Peter Zijlstra
2019-10-18  7:44           ` Dietmar Eggemann
2019-10-18  7:59             ` Peter Zijlstra
2019-10-18 17:24               ` Douglas Raillard
2019-10-18  8:11             ` Peter Zijlstra
2019-10-17 14:23       ` Douglas Raillard
2019-10-17 14:53         ` Peter Zijlstra
2019-10-17 19:07         ` Peter Zijlstra
2019-10-18 11:46           ` Douglas Raillard
2019-10-18 12:07             ` Peter Zijlstra
2019-10-18 14:44               ` Douglas Raillard
2019-10-18 15:15                 ` Vincent Guittot
2019-10-18 16:03                   ` Douglas Raillard
2019-10-18 15:20                 ` Vincent Guittot

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