From cc367732ff0b1c63d0d7bdd11e6d1661794ef6a3 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 15 Oct 2007 17:00:18 +0200 Subject: sched: debug, improve migration statistics add new migration statistics when SCHED_DEBUG and SCHEDSTATS is enabled. Available in /proc//sched. Signed-off-by: Ingo Molnar --- kernel/sched.c | 76 +++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 54 insertions(+), 22 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 945ab1322e1..3b27c3a553a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1005,6 +1005,23 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) #ifdef CONFIG_SMP +/* + * Is this task likely cache-hot: + */ +static inline int +task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) +{ + s64 delta; + + if (p->sched_class != &fair_sched_class) + return 0; + + delta = now - p->se.exec_start; + + return delta < (s64)sysctl_sched_migration_cost; +} + + void set_task_cpu(struct task_struct *p, unsigned int new_cpu) { int old_cpu = task_cpu(p); @@ -1022,6 +1039,11 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) p->se.sleep_start -= clock_offset; if (p->se.block_start) p->se.block_start -= clock_offset; + if (old_cpu != new_cpu) { + schedstat_inc(p, se.nr_migrations); + if (task_hot(p, old_rq->clock, NULL)) + schedstat_inc(p, se.nr_forced2_migrations); + } #endif p->se.vruntime -= old_cfsrq->min_vruntime - new_cfsrq->min_vruntime; @@ -1394,8 +1416,13 @@ static int wake_idle(int cpu, struct task_struct *p) if (sd->flags & SD_WAKE_IDLE) { cpus_and(tmp, sd->span, p->cpus_allowed); for_each_cpu_mask(i, tmp) { - if (idle_cpu(i)) + if (idle_cpu(i)) { + if (i != task_cpu(p)) { + schedstat_inc(p, + se.nr_wakeups_idle); + } return i; + } } } else { break; @@ -1426,7 +1453,7 @@ static inline int wake_idle(int cpu, struct task_struct *p) */ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) { - int cpu, this_cpu, success = 0; + int cpu, orig_cpu, this_cpu, success = 0; unsigned long flags; long old_state; struct rq *rq; @@ -1445,6 +1472,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) goto out_running; cpu = task_cpu(p); + orig_cpu = cpu; this_cpu = smp_processor_id(); #ifdef CONFIG_SMP @@ -1488,6 +1516,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) unsigned long tl = this_load; unsigned long tl_per_task; + schedstat_inc(p, se.nr_wakeups_affine_attempts); tl_per_task = cpu_avg_load_per_task(this_cpu); /* @@ -1507,6 +1536,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) * there is no bad imbalance. */ schedstat_inc(this_sd, ttwu_move_affine); + schedstat_inc(p, se.nr_wakeups_affine); goto out_set_cpu; } } @@ -1518,6 +1548,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) if (this_sd->flags & SD_WAKE_BALANCE) { if (imbalance*this_load <= 100*load) { schedstat_inc(this_sd, ttwu_move_balance); + schedstat_inc(p, se.nr_wakeups_passive); goto out_set_cpu; } } @@ -1543,6 +1574,15 @@ out_set_cpu: out_activate: #endif /* CONFIG_SMP */ + schedstat_inc(p, se.nr_wakeups); + if (sync) + schedstat_inc(p, se.nr_wakeups_sync); + if (orig_cpu != cpu) + schedstat_inc(p, se.nr_wakeups_migrate); + if (cpu == this_cpu) + schedstat_inc(p, se.nr_wakeups_local); + else + schedstat_inc(p, se.nr_wakeups_remote); update_rq_clock(rq); activate_task(rq, p, 1); /* @@ -2118,22 +2158,6 @@ static void pull_task(struct rq *src_rq, struct task_struct *p, check_preempt_curr(this_rq, p); } -/* - * Is this task likely cache-hot: - */ -static inline int -task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) -{ - s64 delta; - - if (p->sched_class != &fair_sched_class) - return 0; - - delta = now - p->se.exec_start; - - return delta < (s64)sysctl_sched_migration_cost; -} - /* * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? */ @@ -2148,12 +2172,16 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, * 2) cannot be migrated to this CPU due to cpus_allowed, or * 3) are cache-hot on their current CPU. */ - if (!cpu_isset(this_cpu, p->cpus_allowed)) + if (!cpu_isset(this_cpu, p->cpus_allowed)) { + schedstat_inc(p, se.nr_failed_migrations_affine); return 0; + } *all_pinned = 0; - if (task_running(rq, p)) + if (task_running(rq, p)) { + schedstat_inc(p, se.nr_failed_migrations_running); return 0; + } /* * Aggressive migration if: @@ -2163,14 +2191,18 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, if (sd->nr_balance_failed > sd->cache_nice_tries) { #ifdef CONFIG_SCHEDSTATS - if (task_hot(p, rq->clock, sd)) + if (task_hot(p, rq->clock, sd)) { schedstat_inc(sd, lb_hot_gained[idle]); + schedstat_inc(p, se.nr_forced_migrations); + } #endif return 1; } - if (task_hot(p, rq->clock, sd)) + if (task_hot(p, rq->clock, sd)) { + schedstat_inc(p, se.nr_failed_migrations_hot); return 0; + } return 1; } -- cgit v1.2.3