[PATCH v3 08/12] sched: move cfs task on a CPU with higher capacity
From: peterz@infradead.org (Peter Zijlstra)
Date: 2014-07-10 11:31:24
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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().
quoted hunk ↗ jump to hunk
@@ -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; }