From 098fb9db2c74cfd6ffdbf61eb026a0c21abc5f75 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 16 Mar 2008 20:36:10 +0100 Subject: [PATCH] sched: clean up wakeup balancing, move wake_affine() split out the affine-wakeup bits. No code changed: kernel/sched.o: text data bss dec hex filename 42521 2858 232 45611 b22b sched.o.before 42521 2858 232 45611 b22b sched.o.after md5: 9d76738f1272aa82f0b7affd2f51df6b sched.o.before.asm 09b31c44e9aff8666f72773dc433e2df sched.o.after.asm (the md5's changed because stack slots changed and some registers get scheduled by gcc in a different order - but otherwise the before and after assembly is instruction for instruction equivalent.) Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 134 +++++++++++++++++++++++++------------------- 1 file changed, 75 insertions(+), 59 deletions(-) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index f2cc59080efa..70679b266693 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -980,12 +980,59 @@ static inline int wake_idle(int cpu, struct task_struct *p) #endif #ifdef CONFIG_SMP + +static int +wake_affine(struct rq *rq, struct sched_domain *this_sd, struct task_struct *p, + int cpu, int this_cpu, int sync, int idx, + unsigned long load, unsigned long this_load, + unsigned int imbalance) +{ + unsigned long tl = this_load; + unsigned long tl_per_task; + + if (!(this_sd->flags & SD_WAKE_AFFINE)) + return 0; + + /* + * Attract cache-cold tasks on sync wakeups: + */ + if (sync && !task_hot(p, rq->clock, this_sd)) + return 1; + + schedstat_inc(p, se.nr_wakeups_affine_attempts); + tl_per_task = cpu_avg_load_per_task(this_cpu); + + /* + * If sync wakeup then subtract the (maximum possible) + * effect of the currently running task from the load + * of the current CPU: + */ + if (sync) + tl -= current->se.load.weight; + + if ((tl <= load && tl + target_load(cpu, idx) <= tl_per_task) || + 100*(tl + p->se.load.weight) <= imbalance*load) { + /* + * This domain has SD_WAKE_AFFINE and + * p is cache cold in this domain, and + * there is no bad imbalance. + */ + schedstat_inc(this_sd, ttwu_move_affine); + schedstat_inc(p, se.nr_wakeups_affine); + + return 1; + } + return 0; +} + static int select_task_rq_fair(struct task_struct *p, int sync) { - int cpu, this_cpu; - struct rq *rq; struct sched_domain *sd, *this_sd = NULL; - int new_cpu; + unsigned long load, this_load; + int cpu, this_cpu, new_cpu; + unsigned int imbalance; + struct rq *rq; + int idx; cpu = task_cpu(p); rq = task_rq(p); @@ -1008,66 +1055,35 @@ static int select_task_rq_fair(struct task_struct *p, int sync) /* * Check for affine wakeup and passive balancing possibilities. */ - if (this_sd) { - int idx = this_sd->wake_idx; - unsigned int imbalance; - unsigned long load, this_load; - - imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; - - load = source_load(cpu, idx); - this_load = target_load(this_cpu, idx); - - new_cpu = this_cpu; /* Wake to this CPU if we can */ - - if (this_sd->flags & SD_WAKE_AFFINE) { - unsigned long tl = this_load; - unsigned long tl_per_task; - - /* - * Attract cache-cold tasks on sync wakeups: - */ - if (sync && !task_hot(p, rq->clock, this_sd)) - goto out_set_cpu; - - schedstat_inc(p, se.nr_wakeups_affine_attempts); - tl_per_task = cpu_avg_load_per_task(this_cpu); - - /* - * If sync wakeup then subtract the (maximum possible) - * effect of the currently running task from the load - * of the current CPU: - */ - if (sync) - tl -= current->se.load.weight; - - if ((tl <= load && - tl + target_load(cpu, idx) <= tl_per_task) || - 100*(tl + p->se.load.weight) <= imbalance*load) { - /* - * This domain has SD_WAKE_AFFINE and - * p is cache cold in this domain, and - * there is no bad imbalance. - */ - schedstat_inc(this_sd, ttwu_move_affine); - schedstat_inc(p, se.nr_wakeups_affine); - goto out_set_cpu; - } - } + if (!this_sd) + goto out_keep_cpu; - /* - * Start passive balancing when half the imbalance_pct - * limit is reached. - */ - 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; - } + idx = this_sd->wake_idx; + + imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; + + load = source_load(cpu, idx); + this_load = target_load(this_cpu, idx); + + new_cpu = this_cpu; /* Wake to this CPU if we can */ + + if (wake_affine(rq, this_sd, p, cpu, this_cpu, sync, idx, + load, this_load, imbalance)) + goto out_set_cpu; + + /* + * Start passive balancing when half the imbalance_pct + * limit is reached. + */ + 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; } } +out_keep_cpu: new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ out_set_cpu: return wake_idle(new_cpu, p); -- 2.20.1