From 2087a1ad822cd3a68b73338457047fcc54da726b Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Fri, 27 Jun 2008 14:30:00 -0600 Subject: [PATCH] sched: add avg-overlap support to RT tasks We have the notion of tracking process-coupling (a.k.a. buddy-wake) via the p->se.last_wake / p->se.avg_overlap facilities, but it is only used for cfs to cfs interactions. There is no reason why an rt to cfs interaction cannot share in establishing a relationhip in a similar manner. Because PREEMPT_RT runs many kernel threads as FIFO priority, we often times have heavy interaction between RT threads waking CFS applications. This patch offers a substantial boost (50-60%+) in perfomance under those circumstances. Signed-off-by: Gregory Haskins Cc: npiggin@suse.de Cc: rostedt@goodmis.org Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 14 ++++++++++++++ kernel/sched_fair.c | 21 ++------------------- 2 files changed, 16 insertions(+), 19 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index d99aeabeb72f..bbc40c3a0657 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1693,6 +1693,12 @@ static void set_load_weight(struct task_struct *p) p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; } +static void update_avg(u64 *avg, u64 sample) +{ + s64 diff = sample - *avg; + *avg += diff >> 3; +} + static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) { sched_info_queued(p); @@ -1702,6 +1708,12 @@ static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) { + if (sleep && p->se.last_wakeup) { + update_avg(&p->se.avg_overlap, + p->se.sum_exec_runtime - p->se.last_wakeup); + p->se.last_wakeup = 0; + } + p->sched_class->dequeue_task(rq, p, sleep); p->se.on_rq = 0; } @@ -2313,6 +2325,8 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) p->sched_class->task_wake_up(rq, p); #endif out: + current->se.last_wakeup = current->se.sum_exec_runtime; + task_rq_unlock(rq, &flags); return success; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 2e43d4a748c3..f2aa987027d6 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -726,21 +726,6 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) __enqueue_entity(cfs_rq, se); } -static void update_avg(u64 *avg, u64 sample) -{ - s64 diff = sample - *avg; - *avg += diff >> 3; -} - -static void update_avg_stats(struct cfs_rq *cfs_rq, struct sched_entity *se) -{ - if (!se->last_wakeup) - return; - - update_avg(&se->avg_overlap, se->sum_exec_runtime - se->last_wakeup); - se->last_wakeup = 0; -} - static void dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) { @@ -751,7 +736,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) update_stats_dequeue(cfs_rq, se); if (sleep) { - update_avg_stats(cfs_rq, se); #ifdef CONFIG_SCHEDSTATS if (entity_is_task(se)) { struct task_struct *tsk = task_of(se); @@ -1196,9 +1180,9 @@ wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq, * a reasonable amount of time then attract this newly * woken task: */ - if (sync && balanced && curr->sched_class == &fair_sched_class) { + if (sync && balanced) { if (curr->se.avg_overlap < sysctl_sched_migration_cost && - p->se.avg_overlap < sysctl_sched_migration_cost) + p->se.avg_overlap < sysctl_sched_migration_cost) return 1; } @@ -1359,7 +1343,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p) return; } - se->last_wakeup = se->sum_exec_runtime; if (unlikely(se == pse)) return; -- GitLab