From 2dac754e10a5d41d94d2d2365c0345d4f215a266 Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Thu, 4 Oct 2012 13:18:30 +0200 Subject: [PATCH] sched: Aggregate load contributed by task entities on parenting cfs_rq For a given task t, we can compute its contribution to load as: task_load(t) = runnable_avg(t) * weight(t) On a parenting cfs_rq we can then aggregate: runnable_load(cfs_rq) = \Sum task_load(t), for all runnable children t Maintain this bottom up, with task entities adding their contributed load to the parenting cfs_rq sum. When a task entity's load changes we add the same delta to the maintained sum. Signed-off-by: Paul Turner Reviewed-by: Ben Segall Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120823141506.514678907@google.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + kernel/sched/debug.c | 3 +++ kernel/sched/fair.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++---- kernel/sched/sched.h | 10 +++++++++- 4 files changed, 60 insertions(+), 5 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 418fc6d..81d8b1b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1103,6 +1103,7 @@ struct sched_avg { */ u32 runnable_avg_sum, runnable_avg_period; u64 last_runnable_update; + unsigned long load_avg_contrib; }; #ifdef CONFIG_SCHEDSTATS diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 4240abc..c953a89 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -94,6 +94,7 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group #ifdef CONFIG_SMP P(se->avg.runnable_avg_sum); P(se->avg.runnable_avg_period); + P(se->avg.load_avg_contrib); #endif #undef PN #undef P @@ -224,6 +225,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) cfs_rq->load_contribution); SEQ_printf(m, " .%-30s: %d\n", "load_tg", atomic_read(&cfs_rq->tg->load_weight)); + SEQ_printf(m, " .%-30s: %lld\n", "runnable_load_avg", + cfs_rq->runnable_load_avg); #endif print_cfs_group_stats(m, cpu, cfs_rq->tg); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8c5468f..77af759 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1081,20 +1081,63 @@ static __always_inline int __update_entity_runnable_avg(u64 now, return decayed; } +/* Compute the current contribution to load_avg by se, return any delta */ +static long __update_entity_load_avg_contrib(struct sched_entity *se) +{ + long old_contrib = se->avg.load_avg_contrib; + + if (!entity_is_task(se)) + return 0; + + se->avg.load_avg_contrib = div64_u64(se->avg.runnable_avg_sum * + se->load.weight, + se->avg.runnable_avg_period + 1); + + return se->avg.load_avg_contrib - old_contrib; +} + /* Update a sched_entity's runnable average */ static inline void update_entity_load_avg(struct sched_entity *se) { - __update_entity_runnable_avg(rq_of(cfs_rq_of(se))->clock_task, &se->avg, - se->on_rq); + struct cfs_rq *cfs_rq = cfs_rq_of(se); + long contrib_delta; + + if (!__update_entity_runnable_avg(rq_of(cfs_rq)->clock_task, &se->avg, + se->on_rq)) + return; + + contrib_delta = __update_entity_load_avg_contrib(se); + if (se->on_rq) + cfs_rq->runnable_load_avg += contrib_delta; } static inline void update_rq_runnable_avg(struct rq *rq, int runnable) { __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable); } + +/* Add the load generated by se into cfs_rq's child load-average */ +static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, + struct sched_entity *se) +{ + update_entity_load_avg(se); + cfs_rq->runnable_load_avg += se->avg.load_avg_contrib; +} + +/* Remove se's load from this cfs_rq child load-average */ +static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq, + struct sched_entity *se) +{ + update_entity_load_avg(se); + cfs_rq->runnable_load_avg -= se->avg.load_avg_contrib; +} #else static inline void update_entity_load_avg(struct sched_entity *se) {} static inline void update_rq_runnable_avg(struct rq *rq, int runnable) {} +static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, + struct sched_entity *se) {} +static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq, + struct sched_entity *se) {} #endif static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) @@ -1223,7 +1266,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) */ update_curr(cfs_rq); update_cfs_load(cfs_rq, 0); - update_entity_load_avg(se); + enqueue_entity_load_avg(cfs_rq, se); account_entity_enqueue(cfs_rq, se); update_cfs_shares(cfs_rq); @@ -1298,7 +1341,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * Update run-time statistics of the 'current'. */ update_curr(cfs_rq); - update_entity_load_avg(se); + dequeue_entity_load_avg(cfs_rq, se); update_stats_dequeue(cfs_rq, se); if (flags & DEQUEUE_SLEEP) { diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 14b5719..e653973 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -222,6 +222,15 @@ struct cfs_rq { unsigned int nr_spread_over; #endif +#ifdef CONFIG_SMP + /* + * CFS Load tracking + * Under CFS, load is tracked on a per-entity basis and aggregated up. + * This allows for the description of both thread and group usage (in + * the FAIR_GROUP_SCHED case). + */ + u64 runnable_load_avg; +#endif #ifdef CONFIG_FAIR_GROUP_SCHED struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ @@ -1214,4 +1223,3 @@ static inline u64 irq_time_read(int cpu) } #endif /* CONFIG_64BIT */ #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ - -- 2.7.4