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From: douglas.raillard@arm.com
To: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org, mingo@redhat.com, peterz@infradead.org,
	quentin.perret@arm.com, douglas.raillard@arm.com,
	patrick.bellasi@arm.com, dietmar.eggemann@arm.com
Subject: [RFC PATCH 1/7] PM: Introduce em_pd_get_higher_freq()
Date: Wed,  8 May 2019 18:42:55 +0100
Message-ID: <20190508174301.4828-2-douglas.raillard@arm.com> (raw)
Message-ID: <20190508174255.bob8KkYeQlIRDxxw15UWyxgJIXy6KRADxhcNCRioOv8@z> (raw)
In-Reply-To: <20190508174301.4828-1-douglas.raillard@arm.com>

From: Douglas RAILLARD <douglas.raillard@arm.com>

em_pd_get_higher_freq() returns a frequency greater or equal to the
provided one while taking into account a given cost margin. It also
skips inefficient OPPs that have a higher cost than another one with a
higher frequency.

Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>
---
 include/linux/energy_model.h | 48 ++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index aa027f7bcb3e..797b4e0f758c 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -159,6 +159,48 @@ static inline int em_pd_nr_cap_states(struct em_perf_domain *pd)
 	return pd->nr_cap_states;
 }
 
+/**
+ * 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, as a per-1024 value.
+ *
+ * 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) / 1024;
+			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;
+}
+
 #else
 struct em_perf_domain {};
 struct em_data_callback {};
@@ -182,6 +224,12 @@ static inline int em_pd_nr_cap_states(struct em_perf_domain *pd)
 {
 	return 0;
 }
+
+static inline unsigned long em_pd_get_higher_freq(struct em_perf_domain *pd,
+	unsigned long min_freq, unsigned long cost_margin)
+{
+	return min_freq;
+}
 #endif
 
 #endif
-- 
2.21.0


  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 ` douglas.raillard [this message]
2019-05-08 17:42   ` [RFC PATCH 1/7] PM: Introduce em_pd_get_higher_freq() douglas.raillard
2019-05-16 12:42   ` Patrick Bellasi
2019-05-16 12:42     ` Patrick Bellasi
2019-05-16 13:01     ` Quentin Perret
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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