[RFCv3 PATCH 36/48] sched: Count number of shallower idle-states in struct sched_group_energy

[Morten Rasmussen]

cpuidle associates all idle-states with each cpu while the energy model
associates them with the sched_group covering the cpus coordinating
entry to the idle-state. To get idle-state power consumption it is
therefore necessary to translate from cpuidle idle-state index to energy
model index. For this purpose it is helpful to know how many idle-states
that are listed in lower level sched_groups (in struct
sched_group_energy).

cc: Ingo Molnar <mingo@xxxxxxxxxx>
cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Signed-off-by: Morten Rasmussen <morten.rasmussen@xxxxxxx>
---
 include/linux/sched.h |  1 +
 kernel/sched/core.c   | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 78b6eb7..f984b4e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -958,6 +958,7 @@ struct sched_group_energy {
 	atomic_t ref;
 	unsigned int nr_idle_states;	/* number of idle states */
 	struct idle_state *idle_states;	/* ptr to idle state array */
+	unsigned int idle_states_below; /* Number idle states in lower groups */
 	unsigned int nr_cap_states;	/* number of capacity states */
 	struct capacity_state *cap_states; /* ptr to capacity state array */
 };
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e47febf..4f52c2e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6075,6 +6075,7 @@ static void init_sched_energy(int cpu, struct sched_domain *sd,
 	struct sched_group_energy *energy = sg->sge;
 	sched_domain_energy_f fn = tl->energy;
 	struct cpumask *mask = sched_group_cpus(sg);
+	int idle_states_below = 0;
 
 	if (!fn || !fn(cpu))
 		return;
@@ -6082,9 +6083,20 @@ static void init_sched_energy(int cpu, struct sched_domain *sd,
 	if (cpumask_weight(mask) > 1)
 		check_sched_energy_data(cpu, fn, mask);
 
+	/* Figure out the number of true cpuidle states below current group */
+	sd = sd->child;
+	for_each_lower_domain(sd) {
+		idle_states_below += sd->groups->sge->nr_idle_states;
+
+		/* Disregard non-cpuidle 'active' idle states */
+		if (sd->child)
+			idle_states_below--;
+	}
+
 	energy->nr_idle_states = fn(cpu)->nr_idle_states;
 	memcpy(energy->idle_states, fn(cpu)->idle_states,
 	       energy->nr_idle_states*sizeof(struct idle_state));
+	energy->idle_states_below = idle_states_below;
 	energy->nr_cap_states = fn(cpu)->nr_cap_states;
 	memcpy(energy->cap_states, fn(cpu)->cap_states,
 	       energy->nr_cap_states*sizeof(struct capacity_state));
-- 
1.9.1

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