>From 51c4dbafa5601d0da46438720186201f5ff00268 Mon Sep 17 00:00:00 2001 From: Chris Redpath Date: Thu, 9 May 2013 16:21:29 +0100 Subject: HMP: Avoid multiple calls to hmp_domain_min_load in fast path When evaluating a migration we make two calls to hmp_domain_min_load. This is unnecessary if we pass on the target CPU information from the hmp_up_migration path. In hmp_down_migration, we don't consider the load of the target CPUS. Signed-off-by: Chris Redpath Signed-off-by: Liviu Dudau --- kernel/sched/fair.c | 36 ++++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 16 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index d7303c5..a38a3ed 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3596,7 +3596,7 @@ unsigned int hmp_up_prio = NICE_TO_PRIO(CONFIG_SCHED_HMP_PRIO_FILTER_VAL); unsigned int hmp_next_up_threshold = 4096; unsigned int hmp_next_down_threshold = 4096; -static unsigned int hmp_up_migration(int cpu, struct sched_entity *se); +static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_entity *se); static unsigned int hmp_down_migration(int cpu, struct sched_entity *se); static inline unsigned int hmp_domain_min_load(struct hmp_domain *hmpd, int *min_cpu); @@ -4032,8 +4032,7 @@ unlock: rcu_read_unlock(); #ifdef CONFIG_SCHED_HMP - if (hmp_up_migration(prev_cpu, &p->se)) { - new_cpu = hmp_select_faster_cpu(p, prev_cpu); + if (hmp_up_migration(prev_cpu, &new_cpu, &p->se)) { hmp_next_up_delay(&p->se, new_cpu); trace_sched_hmp_migrate(p, new_cpu, 0); return new_cpu; @@ -6320,12 +6319,15 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { } #ifdef CONFIG_SCHED_HMP /* Check if task should migrate to a faster cpu */ -static unsigned int hmp_up_migration(int cpu, struct sched_entity *se) +static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_entity *se) { struct task_struct *p = task_of(se); struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs; u64 now; + if (target_cpu) + *target_cpu = NR_CPUS; + if (hmp_cpu_is_fastest(cpu)) return 0; @@ -6334,6 +6336,8 @@ static unsigned int hmp_up_migration(int cpu, struct sched_entity *se) if (p->prio >= hmp_up_prio) return 0; #endif + if (se->avg.load_avg_ratio < hmp_up_threshold) + return 0; /* Let the task load settle before doing another up migration */ now = cfs_rq_clock_task(cfs_rq); @@ -6341,15 +6345,15 @@ static unsigned int hmp_up_migration(int cpu, struct sched_entity *se) < hmp_next_up_threshold) return 0; - if (se->avg.load_avg_ratio > hmp_up_threshold) { - /* Target domain load < ~94% */ - if (hmp_domain_min_load(hmp_faster_domain(cpu), NULL) - > NICE_0_LOAD-64) - return 0; - if (cpumask_intersects(&hmp_faster_domain(cpu)->cpus, - tsk_cpus_allowed(p))) - return 1; - } + /* Target domain load < 94% */ + if (hmp_domain_min_load(hmp_faster_domain(cpu), target_cpu) + > NICE_0_LOAD-64) + return 0; + + if (cpumask_intersects(&hmp_faster_domain(cpu)->cpus, + tsk_cpus_allowed(p))) + return 1; + return 0; } @@ -6542,7 +6546,7 @@ static DEFINE_SPINLOCK(hmp_force_migration); */ static void hmp_force_up_migration(int this_cpu) { - int cpu; + int cpu, target_cpu; struct sched_entity *curr; struct rq *target; unsigned long flags; @@ -6570,10 +6574,10 @@ static void hmp_force_up_migration(int this_cpu) } } p = task_of(curr); - if (hmp_up_migration(cpu, curr)) { + if (hmp_up_migration(cpu, &target_cpu, curr)) { if (!target->active_balance) { target->active_balance = 1; - target->push_cpu = hmp_select_faster_cpu(p, cpu); + target->push_cpu = target_cpu; target->migrate_task = p; force = 1; trace_sched_hmp_migrate(p, target->push_cpu, 1); -- 1.7.9.5