Messages in this thread | | | Date | Wed, 6 Apr 2022 19:25:46 +0200 | From | Dietmar Eggemann <> | Subject | Re: [PATCH] sched/fair: Return the busiest group only if imbalance is meaningful |
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On 06/04/2022 17:33, Vincent Guittot wrote: > On Wed, 6 Apr 2022 at 17:07, 彭志刚 <zgpeng.linux@gmail.com> wrote:
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> I think that this case should be covered by an additional test in > calculate_imbalance because we should not try to pull load in groupA > if it's already above the average load. Something like below should > cover this > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -9469,6 +9469,16 @@ static inline void calculate_imbalance(struct > lb_env *env, struct sd_lb_stats *s > > sds->avg_load = (sds->total_load * SCHED_CAPACITY_SCALE) / > sds->total_capacity; > + > + /* > + * Don't pull any tasks if this group is already above the > + * domain average load. > + */ > + if (local->avg_load >= sds->avg_load) { > + env->imbalance = 0; > + return; > + } > +
LGTM. Like for the `local->group_type == group_overloaded` case in find_busiest_group() where we force `goto out_balanced`.
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