Messages in this thread Patch in this message | | | Subject | [PATCH 03/16] sched: aggregate load contributed by task entities on parenting cfs_rq | From | Paul Turner <> | Date | Wed, 27 Jun 2012 19:24:14 -0700 |
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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 entities load changes we add the same delta to the maintained sum.
Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Ben Segall <bsegall@google.com> --- 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 5bf5c79..0c54ce0 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1139,6 +1139,7 @@ struct load_weight { 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 5d4a7dd..aeb74e3 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 @@ -227,6 +228,8 @@ 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 08bd3e0..8229766 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1085,20 +1085,63 @@ 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) @@ -1227,7 +1270,7 @@ 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); @@ -1302,7 +1345,7 @@ 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 bfdb119..26cc36f 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 */ @@ -1204,4 +1213,3 @@ static inline void account_numa_dequeue(struct task_struct *p) { } static inline void init_sched_numa(void) { } #endif /* CONFIG_NUMA */ -
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