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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