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sched: Scale down cpu_power due to RT tasks
Keep an average on the amount of time spend on RT tasks and use that fraction to scale down the cpu_power for regular tasks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.287778431@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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parent
ab29230e67
commit
e9e9250bc7
4 changed files with 72 additions and 7 deletions
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@ -1831,6 +1831,7 @@ extern unsigned int sysctl_sched_child_runs_first;
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extern unsigned int sysctl_sched_features;
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extern unsigned int sysctl_sched_migration_cost;
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extern unsigned int sysctl_sched_nr_migrate;
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extern unsigned int sysctl_sched_time_avg;
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extern unsigned int sysctl_timer_migration;
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int sched_nr_latency_handler(struct ctl_table *table, int write,
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@ -627,6 +627,9 @@ struct rq {
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struct task_struct *migration_thread;
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struct list_head migration_queue;
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u64 rt_avg;
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u64 age_stamp;
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#endif
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/* calc_load related fields */
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@ -862,6 +865,14 @@ unsigned int sysctl_sched_shares_ratelimit = 250000;
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*/
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unsigned int sysctl_sched_shares_thresh = 4;
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/*
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* period over which we average the RT time consumption, measured
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* in ms.
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*
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* default: 1s
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*/
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const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
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/*
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* period over which we measure -rt task cpu usage in us.
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* default: 1s
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@ -1280,12 +1291,37 @@ void wake_up_idle_cpu(int cpu)
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}
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#endif /* CONFIG_NO_HZ */
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static u64 sched_avg_period(void)
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{
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return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
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}
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static void sched_avg_update(struct rq *rq)
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{
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s64 period = sched_avg_period();
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while ((s64)(rq->clock - rq->age_stamp) > period) {
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rq->age_stamp += period;
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rq->rt_avg /= 2;
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}
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}
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static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
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{
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rq->rt_avg += rt_delta;
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sched_avg_update(rq);
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}
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#else /* !CONFIG_SMP */
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static void resched_task(struct task_struct *p)
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{
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assert_spin_locked(&task_rq(p)->lock);
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set_tsk_need_resched(p);
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}
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static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
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{
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}
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#endif /* CONFIG_SMP */
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#if BITS_PER_LONG == 32
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@ -3699,7 +3735,7 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
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}
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#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
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unsigned long __weak arch_smt_gain(struct sched_domain *sd, int cpu)
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unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
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{
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unsigned long weight = cpumask_weight(sched_domain_span(sd));
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unsigned long smt_gain = sd->smt_gain;
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@ -3709,6 +3745,24 @@ unsigned long __weak arch_smt_gain(struct sched_domain *sd, int cpu)
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return smt_gain;
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}
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unsigned long scale_rt_power(int cpu)
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{
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struct rq *rq = cpu_rq(cpu);
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u64 total, available;
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sched_avg_update(rq);
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total = sched_avg_period() + (rq->clock - rq->age_stamp);
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available = total - rq->rt_avg;
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if (unlikely((s64)total < SCHED_LOAD_SCALE))
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total = SCHED_LOAD_SCALE;
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total >>= SCHED_LOAD_SHIFT;
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return div_u64(available, total);
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}
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static void update_cpu_power(struct sched_domain *sd, int cpu)
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{
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unsigned long weight = cpumask_weight(sched_domain_span(sd));
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@ -3719,11 +3773,15 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
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/* here we could scale based on cpufreq */
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if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
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power *= arch_smt_gain(sd, cpu);
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power *= arch_scale_smt_power(sd, cpu);
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power >>= SCHED_LOAD_SHIFT;
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}
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/* here we could scale based on RT time */
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power *= scale_rt_power(cpu);
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power >>= SCHED_LOAD_SHIFT;
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if (!power)
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power = 1;
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if (power != old) {
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sdg->__cpu_power = power;
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@ -615,6 +615,8 @@ static void update_curr_rt(struct rq *rq)
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curr->se.exec_start = rq->clock;
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cpuacct_charge(curr, delta_exec);
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sched_rt_avg_update(rq, delta_exec);
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if (!rt_bandwidth_enabled())
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return;
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@ -887,8 +889,6 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
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if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
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enqueue_pushable_task(rq, p);
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inc_cpu_load(rq, p->se.load.weight);
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}
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static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
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@ -899,8 +899,6 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
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dequeue_rt_entity(rt_se);
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dequeue_pushable_task(rq, p);
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dec_cpu_load(rq, p->se.load.weight);
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}
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/*
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@ -330,6 +330,14 @@ static struct ctl_table kern_table[] = {
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.mode = 0644,
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.proc_handler = &proc_dointvec,
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},
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{
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.ctl_name = CTL_UNNUMBERED,
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.procname = "sched_time_avg",
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.data = &sysctl_sched_time_avg,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = &proc_dointvec,
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},
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{
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.ctl_name = CTL_UNNUMBERED,
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.procname = "timer_migration",
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