From 614f72ff6421e92c35b456aebcfb58601c47cb57 Mon Sep 17 00:00:00 2001 From: Morten Rasmussen Date: Fri, 14 Sep 2012 14:38:17 +0100 Subject: sched: SCHED_HMP multi-domain task migration control We need a way to prevent tasks that are migrating up and down the hmp_domains from migrating straight on through before the load has adapted to the new compute capacity of the CPU on the new hmp_domain. This patch adds a next up/down migration delay that prevents the task from doing another migration in the same direction until the delay has expired. Signed-off-by: Morten Rasmussen --- include/linux/sched.h | 4 ++++ kernel/sched/core.c | 4 ++++ kernel/sched/fair.c | 38 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 46 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index be6f4921b1bc..4b8e94bd1433 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1113,6 +1113,10 @@ struct sched_avg { s64 decay_count; unsigned long load_avg_contrib; unsigned long load_avg_ratio; +#ifdef CONFIG_SCHED_HMP + u64 hmp_last_up_migration; + u64 hmp_last_down_migration; +#endif u32 usage_avg_sum; }; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5dae0d252ff7..8184cc51ed08 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1534,6 +1534,10 @@ static void __sched_fork(struct task_struct *p) #if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED) p->se.avg.runnable_avg_period = 0; p->se.avg.runnable_avg_sum = 0; +#ifdef CONFIG_SCHED_HMP + p->se.avg.hmp_last_up_migration = 0; + p->se.avg.hmp_last_down_migration = 0; +#endif #endif #ifdef CONFIG_SCHEDSTATS memset(&p->se.statistics, 0, sizeof(p->se.statistics)); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f1d99c2398a0..e61326042887 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3160,12 +3160,16 @@ static int __init hmp_cpu_mask_setup(void) * tweaking suit particular needs. * * hmp_up_prio: Only up migrate task with high priority (cfs; + + se->avg.hmp_last_up_migration = cfs_rq_clock_task(cfs_rq); + se->avg.hmp_last_down_migration = 0; +} + +static inline void hmp_next_down_delay(struct sched_entity *se, int cpu) +{ + struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs; + + se->avg.hmp_last_down_migration = cfs_rq_clock_task(cfs_rq); + se->avg.hmp_last_up_migration = 0; +} #endif /* CONFIG_SCHED_HMP */ /* @@ -3331,11 +3350,13 @@ unlock: #ifdef CONFIG_SCHED_HMP if (hmp_up_migration(prev_cpu, &p->se)) { new_cpu = hmp_select_faster_cpu(p, prev_cpu); + hmp_next_up_delay(&p->se, new_cpu); trace_sched_hmp_migrate(p, new_cpu, 0); return new_cpu; } if (hmp_down_migration(prev_cpu, &p->se)) { new_cpu = hmp_select_slower_cpu(p, prev_cpu); + hmp_next_down_delay(&p->se, new_cpu); trace_sched_hmp_migrate(p, new_cpu, 0); return new_cpu; } @@ -5608,6 +5629,8 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { } static unsigned int hmp_up_migration(int cpu, struct sched_entity *se) { struct task_struct *p = task_of(se); + struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs; + u64 now; if (hmp_cpu_is_fastest(cpu)) return 0; @@ -5618,6 +5641,12 @@ static unsigned int hmp_up_migration(int cpu, struct sched_entity *se) return 0; #endif + /* Let the task load settle before doing another up migration */ + now = cfs_rq_clock_task(cfs_rq); + if (((now - se->avg.hmp_last_up_migration) >> 10) + < hmp_next_up_threshold) + return 0; + if (cpumask_intersects(&hmp_faster_domain(cpu)->cpus, tsk_cpus_allowed(p)) && se->avg.load_avg_ratio > hmp_up_threshold) { @@ -5630,6 +5659,8 @@ static unsigned int hmp_up_migration(int cpu, struct sched_entity *se) static unsigned int hmp_down_migration(int cpu, struct sched_entity *se) { struct task_struct *p = task_of(se); + struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs; + u64 now; if (hmp_cpu_is_slowest(cpu)) return 0; @@ -5640,6 +5671,12 @@ static unsigned int hmp_down_migration(int cpu, struct sched_entity *se) return 1; #endif + /* Let the task load settle before doing another down migration */ + now = cfs_rq_clock_task(cfs_rq); + if (((now - se->avg.hmp_last_down_migration) >> 10) + < hmp_next_down_threshold) + return 0; + if (cpumask_intersects(&hmp_slower_domain(cpu)->cpus, tsk_cpus_allowed(p)) && se->avg.load_avg_ratio < hmp_down_threshold) { @@ -5830,6 +5867,7 @@ static void hmp_force_up_migration(int this_cpu) target->migrate_task = p; force = 1; trace_sched_hmp_migrate(p, target->push_cpu, 1); + hmp_next_up_delay(&p->se, target->push_cpu); } } raw_spin_unlock_irqrestore(&target->lock, flags); -- cgit v1.2.3