| Date | Thu, 29 May 2014 16:04:27 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 10/11] sched: move cfs task on a CPU with higher capacity |
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On Fri, May 23, 2014 at 05:53:04PM +0200, Vincent Guittot wrote: > @@ -7282,6 +7289,12 @@ static inline int nohz_kick_needed(struct rq *rq) > > if (nr_busy > 1) > goto need_kick_unlock; > + > + if ((rq->cfs.h_nr_running >= 1) > + && ((rq->cpu_power * sd->imbalance_pct) < > + (rq->cpu_power_orig * 100))) > + goto need_kick_unlock; > + > } > > sd = rcu_dereference(per_cpu(sd_asym, cpu));
So what happens when a cpu is consistently low on power (say due to a pinned RT task) the balancer would quickly adjust the load level, but this would endlessly kick things into action, even though we're balanced just fine.
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