Re: [PATCH v3 08/12] sched: move cfs task on a CPU with higher capacity

On Mon, Jun 30, 2014 at 06:05:39PM +0200, Vincent Guittot wrote:

You 'forgot' to update the comment that goes with nohz_kick_needed().

@@ -7233,9 +7253,10 @@ static inline int nohz_kick_needed(struct rq *rq) struct sched_domain *sd; struct sched_group_capacity *sgc; int nr_busy, cpu = rq->cpu;

• bool kick = false;

if (unlikely(rq->idle_balance))

• return false;
  

/*

• We may be recently in ticked or tickless idle mode. At the first

@@ -7249,38 +7270,41 @@ static inline int nohz_kick_needed(struct rq *rq) * balancing. */ if (likely(!atomic_read(&nohz.nr_cpus)))

• return false;
  

if (time_before(now, nohz.next_balance))

• return false;
  

if (rq->nr_running >= 2)

• return true;
  

rcu_read_lock(); sd = rcu_dereference(per_cpu(sd_busy, cpu)); if (sd) { sgc = sd->groups->sgc; nr_busy = atomic_read(&sgc->nr_busy_cpus);

• if (nr_busy > 1) {
  

• 	kick = true;
  

• 	goto unlock;
  

• }
  

• if ((rq->cfs.h_nr_running >= 1)
  

•  && ((rq->cpu_capacity * sd->imbalance_pct) <
  

• 			(rq->cpu_capacity_orig * 100))) {
  

• 	kick = true;
  

• 	goto unlock;
  

• }
  

Again, why only for shared caches?

} sd = rcu_dereference(per_cpu(sd_asym, cpu)); if (sd && (cpumask_first_and(nohz.idle_cpus_mask, sched_domain_span(sd)) < cpu))

• kick = true;
  

+unlock: rcu_read_unlock();

• return kick;

}