Messages in this thread Patch in this message | | | Date | Wed, 24 Sep 2014 18:48:15 +0100 | From | Dietmar Eggemann <> | Subject | Re: [PATCH v6 5/6] sched: replace capacity_factor by usage |
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On 23/09/14 17:08, Vincent Guittot wrote:
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> > Finally, the sched_group->sched_group_capacity->capacity_orig has been removed > because it's more used during load balance.
So you're not forced to call it rq->cpu_capacity_orig any more, you could use rq->cpu_capacity_max instead.
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This review (by PeterZ) during v5 of your patch-set recommended some renaming (e.g. s/group_has_free_capacity/group_has_capacity and s/group_out_of_capacity/group_no_capacity as well as reordering of the parameters which I agree with:
https://lkml.org/lkml/2014/9/11/706
> > -/* > - * Compute the group capacity factor. > - * > - * Avoid the issue where N*frac(smt_capacity) >= 1 creates 'phantom' cores by > - * first dividing out the smt factor and computing the actual number of cores > - * and limit unit capacity with that. > - */ > -static inline int sg_capacity_factor(struct lb_env *env, struct sched_group *group) > +static inline int group_has_free_capacity(struct sg_lb_stats *sgs,
s/static inline int/static inline bool
> + struct lb_env *env) > { > - unsigned int capacity_factor, smt, cpus; > - unsigned int capacity, capacity_orig; > + if ((sgs->group_capacity * 100) > > + (sgs->group_usage * env->sd->imbalance_pct)) > + return true; > > - capacity = group->sgc->capacity; > - capacity_orig = group->sgc->capacity_orig; > - cpus = group->group_weight; > + if (sgs->sum_nr_running < sgs->group_weight) > + return true; > > - /* smt := ceil(cpus / capacity), assumes: 1 < smt_capacity < 2 */ > - smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, capacity_orig); > - capacity_factor = cpus / smt; /* cores */ > + return false; > +} > > - capacity_factor = min_t(unsigned, > - capacity_factor, DIV_ROUND_CLOSEST(capacity, SCHED_CAPACITY_SCALE)); > - if (!capacity_factor) > - capacity_factor = fix_small_capacity(env->sd, group); > +static inline int group_is_overloaded(struct sg_lb_stats *sgs,
s/static inline int/static inline bool
> + struct lb_env *env) > +{ > + if (sgs->sum_nr_running <= sgs->group_weight) > + return false; > > - return capacity_factor; > + if ((sgs->group_capacity * 100) < > + (sgs->group_usage * env->sd->imbalance_pct)) > + return true; > + > + return false; > } > > static enum group_type > -group_classify(struct sched_group *group, struct sg_lb_stats *sgs) > +group_classify(struct sched_group *group, struct sg_lb_stats *sgs, > + struct lb_env *env) > { > - if (sgs->sum_nr_running > sgs->group_capacity_factor) > + if (group_is_overloaded(sgs, env)) > return group_overloaded; > > if (sg_imbalanced(group)) > @@ -6072,11 +6038,10 @@ static inline void update_sg_lb_stats(struct lb_env *env, > sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; > > sgs->group_weight = group->group_weight; > - sgs->group_capacity_factor = sg_capacity_factor(env, group); > - sgs->group_type = group_classify(group, sgs); > > - if (sgs->group_capacity_factor > sgs->sum_nr_running) > - sgs->group_has_free_capacity = 1; > + sgs->group_type = group_classify(group, sgs, env); > + > + sgs->group_out_of_capacity = group_is_overloaded(sgs, env);
In case sgs->group_type is group_overloaded you could set sgs->group_out_of_capacity to 1 without calling group_is_overloaded again.
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7cdf271e8e52..52d441c92a4f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6037,7 +6037,8 @@ static inline void update_sg_lb_stats(struct lb_env *env,
sgs->group_type = group_classify(group, sgs, env);
- sgs->group_out_of_capacity = group_is_overloaded(sgs, env); + if (sgs->group_type == group_overloaded) + sgs->group_out_of_capacity = 1; }
> } > > /** > @@ -6198,17 +6163,21 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
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