PM / EM: change naming convention from 'capacity' to 'performance'

The Energy Model uses concept of performance domain and capacity states in
order to calculate power used by CPUs. Change naming convention from
capacity to performance state would enable wider usage in future, e.g.
upcoming support for other devices other than CPUs.

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Quentin Perret <qperret@google.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 46 insertions, 40 deletions

diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index ade6486a3382..fe336a9eb5d4 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -10,13 +10,13 @@
 #include <linux/types.h>
 
 /**
- * em_cap_state - Capacity state of a performance domain
+ * em_perf_state - Performance state of a performance domain
  * @frequency:	The CPU frequency in KHz, for consistency with CPUFreq
  * @power:	The power consumed by 1 CPU at this level, in milli-watts
  * @cost:	The cost coefficient associated with this level, used during
  *		energy calculation. Equal to: power * max_frequency / frequency
  */
-struct em_cap_state {
+struct em_perf_state {
 	unsigned long frequency;
 	unsigned long power;
 	unsigned long cost;
@@ -24,8 +24,8 @@ struct em_cap_state {
 
 /**
  * em_perf_domain - Performance domain
- * @table:		List of capacity states, in ascending order
- * @nr_cap_states:	Number of capacity states
+ * @table:		List of performance states, in ascending order
+ * @nr_perf_states:	Number of performance states
  * @cpus:		Cpumask covering the CPUs of the domain
  *
  * A "performance domain" represents a group of CPUs whose performance is
@@ -34,22 +34,27 @@ struct em_cap_state {
  * CPUFreq policies.
  */
 struct em_perf_domain {
-	struct em_cap_state *table;
-	int nr_cap_states;
+	struct em_perf_state *table;
+	int nr_perf_states;
 	unsigned long cpus[];
 };
 
+#define em_span_cpus(em) (to_cpumask((em)->cpus))
+
 #ifdef CONFIG_ENERGY_MODEL
 #define EM_CPU_MAX_POWER 0xFFFF
 
 struct em_data_callback {
 	/**
-	 * active_power() - Provide power at the next capacity state of a CPU
-	 * @power	: Active power at the capacity state in mW (modified)
-	 * @freq	: Frequency at the capacity state in kHz (modified)
+	 * active_power() - Provide power at the next performance state of
+	 *		a CPU
+	 * @power	: Active power at the performance state in mW
+	 *		(modified)
+	 * @freq	: Frequency at the performance state in kHz
+	 *		(modified)
 	 * @cpu		: CPU for which we do this operation
 	 *
-	 * active_power() must find the lowest capacity state of 'cpu' above
+	 * active_power() must find the lowest performance state of 'cpu' above
 	 * 'freq' and update 'power' and 'freq' to the matching active power
 	 * and frequency.
 	 *
@@ -80,46 +85,46 @@ static inline unsigned long em_pd_energy(struct em_perf_domain *pd,
 				unsigned long max_util, unsigned long sum_util)
 {
 	unsigned long freq, scale_cpu;
-	struct em_cap_state *cs;
+	struct em_perf_state *ps;
 	int i, cpu;
 
 	/*
-	 * In order to predict the capacity state, map the utilization of the
-	 * most utilized CPU of the performance domain to a requested frequency,
-	 * like schedutil.
+	 * In order to predict the performance state, map the utilization of
+	 * the most utilized CPU of the performance domain to a requested
+	 * frequency, like schedutil.
 	 */
 	cpu = cpumask_first(to_cpumask(pd->cpus));
 	scale_cpu = arch_scale_cpu_capacity(cpu);
-	cs = &pd->table[pd->nr_cap_states - 1];
-	freq = map_util_freq(max_util, cs->frequency, scale_cpu);
+	ps = &pd->table[pd->nr_perf_states - 1];
+	freq = map_util_freq(max_util, ps->frequency, scale_cpu);
 
 	/*
-	 * Find the lowest capacity state of the Energy Model above the
+	 * Find the lowest performance state of the Energy Model above the
 	 * requested frequency.
 	 */
-	for (i = 0; i < pd->nr_cap_states; i++) {
-		cs = &pd->table[i];
-		if (cs->frequency >= freq)
+	for (i = 0; i < pd->nr_perf_states; i++) {
+		ps = &pd->table[i];
+		if (ps->frequency >= freq)
 			break;
 	}
 
 	/*
-	 * The capacity of a CPU in the domain at that capacity state (cs)
+	 * The capacity of a CPU in the domain at the performance state (ps)
 	 * can be computed as:
 	 *
-	 *             cs->freq * scale_cpu
-	 *   cs->cap = --------------------                          (1)
+	 *             ps->freq * scale_cpu
+	 *   ps->cap = --------------------                          (1)
 	 *                 cpu_max_freq
 	 *
 	 * So, ignoring the costs of idle states (which are not available in
-	 * the EM), the energy consumed by this CPU at that capacity state is
-	 * estimated as:
+	 * the EM), the energy consumed by this CPU at that performance state
+	 * is estimated as:
 	 *
-	 *             cs->power * cpu_util
+	 *             ps->power * cpu_util
 	 *   cpu_nrg = --------------------                          (2)
-	 *                   cs->cap
+	 *                   ps->cap
 	 *
-	 * since 'cpu_util / cs->cap' represents its percentage of busy time.
+	 * since 'cpu_util / ps->cap' represents its percentage of busy time.
 	 *
 	 *   NOTE: Although the result of this computation actually is in
 	 *         units of power, it can be manipulated as an energy value
@@ -129,34 +134,35 @@ static inline unsigned long em_pd_energy(struct em_perf_domain *pd,
 	 * By injecting (1) in (2), 'cpu_nrg' can be re-expressed as a product
 	 * of two terms:
 	 *
-	 *             cs->power * cpu_max_freq   cpu_util
+	 *             ps->power * cpu_max_freq   cpu_util
 	 *   cpu_nrg = ------------------------ * ---------          (3)
-	 *                    cs->freq            scale_cpu
+	 *                    ps->freq            scale_cpu
 	 *
-	 * The first term is static, and is stored in the em_cap_state struct
-	 * as 'cs->cost'.
+	 * The first term is static, and is stored in the em_perf_state struct
+	 * as 'ps->cost'.
 	 *
 	 * Since all CPUs of the domain have the same micro-architecture, they
-	 * share the same 'cs->cost', and the same CPU capacity. Hence, the
+	 * share the same 'ps->cost', and the same CPU capacity. Hence, the
 	 * total energy of the domain (which is the simple sum of the energy of
 	 * all of its CPUs) can be factorized as:
 	 *
-	 *            cs->cost * \Sum cpu_util
+	 *            ps->cost * \Sum cpu_util
 	 *   pd_nrg = ------------------------                       (4)
 	 *                  scale_cpu
 	 */
-	return cs->cost * sum_util / scale_cpu;
+	return ps->cost * sum_util / scale_cpu;
 }
 
 /**
- * em_pd_nr_cap_states() - Get the number of capacity states of a perf. domain
+ * em_pd_nr_perf_states() - Get the number of performance states of a perf.
+ *				domain
  * @pd		: performance domain for which this must be done
  *
- * Return: the number of capacity states in the performance domain table
+ * Return: the number of performance states in the performance domain table
  */
-static inline int em_pd_nr_cap_states(struct em_perf_domain *pd)
+static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
 {
-	return pd->nr_cap_states;
+	return pd->nr_perf_states;
 }
 
 #else
@@ -177,7 +183,7 @@ static inline unsigned long em_pd_energy(struct em_perf_domain *pd,
 {
 	return 0;
 }
-static inline int em_pd_nr_cap_states(struct em_perf_domain *pd)
+static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
 {
 	return 0;
 }