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From: Quentin Perret <quentin.perret@arm.com>
To: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: douglas.raillard@arm.com, linux-kernel@vger.kernel.org,
	linux-pm@vger.kernel.org, mingo@redhat.com, peterz@infradead.org,
	dietmar.eggemann@arm.com
Subject: Re: [RFC PATCH 1/7] PM: Introduce em_pd_get_higher_freq()
Date: Thu, 16 May 2019 14:01:50 +0100
Message-ID: <20190516130148.uhq55ptut47usnae@queper01-lin> (raw)
In-Reply-To: <20190516124200.opxczohjelhvrzmo@e110439-lin>

On Thursday 16 May 2019 at 13:42:00 (+0100), Patrick Bellasi wrote:
> > +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) / 1024;
>                                                                          ^^^^
> ... end here we should probably better use SCHED_CAPACITY_SCALE
> instead of hard-coding in values, isn't it?

I'm not sure to agree. This isn't part of the scheduler per se, and the
cost thing isn't in units of capacity, but in units of power, so I don't
think SCHED_CAPACITY_SCALE is correct here.

But I agree these hard coded values (that one, and the 512 in one of the
following patches) could use some motivation :-)

Thanks,
Quentin

From: Quentin Perret <quentin.perret@arm.com>
To: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: douglas.raillard@arm.com, linux-kernel@vger.kernel.org,
	linux-pm@vger.kernel.org, mingo@redhat.com, peterz@infradead.org,
	dietmar.eggemann@arm.com
Subject: Re: [RFC PATCH 1/7] PM: Introduce em_pd_get_higher_freq()
Date: Thu, 16 May 2019 14:01:50 +0100
Message-ID: <20190516130148.uhq55ptut47usnae@queper01-lin> (raw)
Message-ID: <20190516130150.8eyDYvkk0JNMvrAn_UEA1qfAUMp3hOmqd5yAqXIkFE8@z> (raw)
In-Reply-To: <20190516124200.opxczohjelhvrzmo@e110439-lin>

On Thursday 16 May 2019 at 13:42:00 (+0100), Patrick Bellasi wrote:
> > +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) / 1024;
>                                                                          ^^^^
> ... end here we should probably better use SCHED_CAPACITY_SCALE
> instead of hard-coding in values, isn't it?

I'm not sure to agree. This isn't part of the scheduler per se, and the
cost thing isn't in units of capacity, but in units of power, so I don't
think SCHED_CAPACITY_SCALE is correct here.

But I agree these hard coded values (that one, and the 512 in one of the
following patches) could use some motivation :-)

Thanks,
Quentin

  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-08 17:42 [RFC PATCH 0/7] sched/cpufreq: Make schedutil energy aware douglas.raillard
2019-05-08 17:42 ` douglas.raillard
2019-05-08 17:42 ` [RFC PATCH 1/7] PM: Introduce em_pd_get_higher_freq() douglas.raillard
2019-05-08 17:42   ` douglas.raillard
2019-05-16 12:42   ` Patrick Bellasi
2019-05-16 12:42     ` Patrick Bellasi
2019-05-16 13:01     ` Quentin Perret [this message]
2019-05-16 13:01       ` Quentin Perret
2019-05-16 13:22       ` Patrick Bellasi
2019-05-16 13:22         ` Patrick Bellasi
2019-06-19 16:08         ` Douglas Raillard
2019-06-20 13:04           ` Patrick Bellasi
2019-06-21 10:17             ` Quentin Perret
2019-06-21 10:22               ` Quentin Perret
2019-05-16 13:06     ` Douglas Raillard
2019-05-16 13:06       ` Douglas Raillard
2019-05-08 17:42 ` [RFC PATCH 2/7] sched/cpufreq: Attach perf domain to sugov policy douglas.raillard
2019-05-08 17:42   ` douglas.raillard
2019-05-08 17:42 ` [RFC PATCH 3/7] sched/cpufreq: Hook em_pd_get_higher_power() into get_next_freq() douglas.raillard
2019-05-08 17:42   ` douglas.raillard
2019-05-08 17:42 ` [RFC PATCH 4/7] sched/cpufreq: Move up sugov_cpu_is_busy() douglas.raillard
2019-05-08 17:42   ` douglas.raillard
2019-05-08 17:42 ` [RFC PATCH 5/7] sched/cpufreq: sugov_cpu_is_busy for shared policy douglas.raillard
2019-05-08 17:42   ` douglas.raillard
2019-05-08 17:43 ` [RFC PATCH 6/7] sched/cpufreq: Improve sugov_cpu_is_busy accuracy douglas.raillard
2019-05-08 17:43   ` douglas.raillard
2019-05-16 12:55   ` Patrick Bellasi
2019-05-16 12:55     ` Patrick Bellasi
2019-06-19 16:19     ` Douglas Raillard
2019-06-20 11:05       ` Patrick Bellasi
2019-05-08 17:43 ` [RFC PATCH 7/7] sched/cpufreq: Boost schedutil frequency ramp up douglas.raillard
2019-05-08 17:43   ` douglas.raillard
2019-05-13  7:12 ` [RFC PATCH 0/7] sched/cpufreq: Make schedutil energy aware Viresh Kumar
2019-05-13  7:12   ` Viresh Kumar
2019-05-13 13:52   ` Douglas Raillard
2019-05-13 13:52     ` Douglas Raillard

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