Messages in this thread Patch in this message | | | Date | Wed, 20 Dec 2017 15:22:02 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 2/2] sched/fair: Update blocked load from newly idle balance |
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On Fri, Dec 01, 2017 at 06:01:57PM +0000, Brendan Jackman wrote: > @@ -7913,6 +7928,29 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd > if (child && child->flags & SD_PREFER_SIBLING) > prefer_sibling = 1; > > +#ifdef CONFIG_NO_HZ_COMMON > + if (env->idle == CPU_NEWLY_IDLE) { > + int cpu; > + > + /* Update the stats of NOHZ idle CPUs in the sd */ > + for_each_cpu_and(cpu, sched_domain_span(env->sd), > + nohz.idle_cpus_mask) { > + struct rq *rq = cpu_rq(cpu); > + > + /* ... Unless we've already done since the last tick */ > + if (time_after(jiffies, rq->last_blocked_load_update_tick)) > + update_blocked_averages(cpu); > + } > + } > + /* > + * If we've just updated all of the NOHZ idle CPUs, then we can push > + * back the next nohz.next_update, which will prevent an unnecessary > + * wakeup for the nohz stats kick > + */ > + if (cpumask_subset(nohz.idle_cpus_mask, sched_domain_span(env->sd))) > + nohz.next_update = jiffies + LOAD_AVG_PERIOD; > +#endif > + > load_idx = get_sd_load_idx(env->sd, env->idle); > > do {
We're already going to be iterating all those CPUs through update_sg_lb_stats(), why not push it all the way down there and avoid the double iteration?
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