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Date: Thu, 25 Apr 2013 19:23:26 +0200
From: Vincent Guittot <vincent.guittot@...aro.org>
To: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linaro-kernel@...ts.linaro.org, peterz@...radead.org,
mingo@...nel.org, linux@....linux.org.uk, pjt@...gle.com,
santosh.shilimkar@...com, Morten.Rasmussen@....com,
chander.kashyap@...aro.org, cmetcalf@...era.com,
tony.luck@...el.com, alex.shi@...el.com, preeti@...ux.vnet.ibm.com
Cc: paulmck@...ux.vnet.ibm.com, tglx@...utronix.de,
len.brown@...el.com, arjan@...ux.intel.com,
amit.kucheria@...aro.org, corbet@....net, l.majewski@...sung.com,
Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH 10/14] sched: update the buddy CPU
Periodically updates the buddy of a CPU according to the current activity of
the system. A CPU is its own buddy if it participates to the packing effort.
Otherwise, it points to a CPU that participates to the packing effort.
Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
kernel/sched/fair.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 86 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 234ecdd..28f8ea7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -174,11 +174,17 @@ void sched_init_granularity(void)
#ifdef CONFIG_SMP
+static unsigned long power_of(int cpu)
+{
+ return cpu_rq(cpu)->cpu_power;
+}
+
/*
* Save the id of the optimal CPU that should be used to pack small tasks
* The value -1 is used when no buddy has been found
*/
DEFINE_PER_CPU(int, sd_pack_buddy);
+DEFINE_PER_CPU(struct sched_domain *, sd_pack_domain);
/*
* Look for the best buddy CPU that can be used to pack small tasks
@@ -237,6 +243,68 @@ void update_packing_domain(int cpu)
}
pr_debug("CPU%d packing on CPU%d\n", cpu, id);
+ per_cpu(sd_pack_domain, cpu) = sd;
+ per_cpu(sd_pack_buddy, cpu) = id;
+}
+
+void update_packing_buddy(int cpu, int activity)
+{
+ struct sched_domain *sd = per_cpu(sd_pack_domain, cpu);
+ struct sched_group *sg, *pack, *tmp;
+ int id = cpu;
+
+ if (!sd)
+ return;
+
+ /*
+ * The sched_domain of a CPU points on the local sched_group
+ * and this CPU of this local group is a good candidate
+ */
+ pack = sg = sd->groups;
+
+ /* loop the sched groups to find the best one */
+ for (tmp = sg->next; tmp != sg; tmp = tmp->next) {
+ if ((tmp->sgp->power * pack->group_weight) >
+ (pack->sgp->power_available * tmp->group_weight))
+ continue;
+
+ if (((tmp->sgp->power * pack->group_weight) ==
+ (pack->sgp->power * tmp->group_weight))
+ && (cpumask_first(sched_group_cpus(tmp)) >= id))
+ continue;
+
+ /* we have found a better group */
+ pack = tmp;
+
+ /* Take the 1st CPU of the new group */
+ id = cpumask_first(sched_group_cpus(pack));
+ }
+
+ if ((cpu == id) || (activity <= power_of(id))) {
+ per_cpu(sd_pack_buddy, cpu) = id;
+ return;
+ }
+
+ for (tmp = pack; activity > 0; tmp = tmp->next) {
+ if (tmp->sgp->power > activity) {
+ id = cpumask_first(sched_group_cpus(tmp));
+ activity -= power_of(id);
+ if (cpu == id)
+ activity = 0;
+ while ((activity > 0) && (id < nr_cpu_ids)) {
+ id = cpumask_next(id, sched_group_cpus(tmp));
+ activity -= power_of(id);
+ if (cpu == id)
+ activity = 0;
+ }
+ } else if (cpumask_test_cpu(cpu, sched_group_cpus(tmp))) {
+ id = cpu;
+ activity = 0;
+ } else {
+ activity -= tmp->sgp->power;
+ }
+ }
+
per_cpu(sd_pack_buddy, cpu) = id;
}
@@ -3014,11 +3082,6 @@ static unsigned long target_load(int cpu, int type)
return max(rq->cpu_load[type-1], total);
}
-static unsigned long power_of(int cpu)
-{
- return cpu_rq(cpu)->cpu_power;
-}
-
static unsigned long cpu_avg_load_per_task(int cpu)
{
struct rq *rq = cpu_rq(cpu);
@@ -4740,6 +4803,22 @@ static bool update_sd_pick_busiest(struct lb_env *env,
return false;
}
+static void update_plb_buddy(int cpu, int *balance, struct sd_lb_stats *sds,
+ struct sched_domain *sd)
+{
+ int buddy;
+
+ if (sysctl_sched_packing_mode != SCHED_PACKING_FULL)
+ return;
+
+ /* Update my buddy */
+ if (sd == per_cpu(sd_pack_domain, cpu))
+ update_packing_buddy(cpu, sds->total_activity);
+
+ /* Get my new buddy */
+ buddy = per_cpu(sd_pack_buddy, cpu);
+}
+
/**
* update_sd_lb_stats - Update sched_domain's statistics for load balancing.
* @env: The load balancing environment.
@@ -4807,6 +4886,8 @@ static inline void update_sd_lb_stats(struct lb_env *env,
sg = sg->next;
} while (sg != env->sd->groups);
+
+ update_plb_buddy(env->dst_cpu, balance, sds, env->sd);
}
/**
--
1.7.9.5
--
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