sched/fair: Add sched_group per-CPU max capacity
The current sg->min_capacity tracks the lowest per-CPU compute capacity available in the sched_group when rt/irq pressure is taken into account. Minimum capacity isn't the ideal metric for tracking if a sched_group needs offloading to another sched_group for some scenarios, e.g. a sched_group with multiple CPUs if only one is under heavy pressure. Tracking maximum capacity isn't perfect either but a better choice for some situations as it indicates that the sched_group definitely compute capacity constrained either due to rt/irq pressure on all CPUs or asymmetric CPU capacities (e.g. big.LITTLE). Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-4-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -7557,13 +7557,14 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu)
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cpu_rq(cpu)->cpu_capacity = capacity;
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cpu_rq(cpu)->cpu_capacity = capacity;
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sdg->sgc->capacity = capacity;
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sdg->sgc->capacity = capacity;
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sdg->sgc->min_capacity = capacity;
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sdg->sgc->min_capacity = capacity;
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sdg->sgc->max_capacity = capacity;
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}
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}
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void update_group_capacity(struct sched_domain *sd, int cpu)
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void update_group_capacity(struct sched_domain *sd, int cpu)
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{
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{
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struct sched_domain *child = sd->child;
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struct sched_domain *child = sd->child;
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struct sched_group *group, *sdg = sd->groups;
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struct sched_group *group, *sdg = sd->groups;
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unsigned long capacity, min_capacity;
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unsigned long capacity, min_capacity, max_capacity;
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unsigned long interval;
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unsigned long interval;
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interval = msecs_to_jiffies(sd->balance_interval);
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interval = msecs_to_jiffies(sd->balance_interval);
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@ -7577,6 +7578,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
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capacity = 0;
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capacity = 0;
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min_capacity = ULONG_MAX;
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min_capacity = ULONG_MAX;
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max_capacity = 0;
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if (child->flags & SD_OVERLAP) {
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if (child->flags & SD_OVERLAP) {
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/*
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/*
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@ -7607,6 +7609,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
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}
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}
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min_capacity = min(capacity, min_capacity);
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min_capacity = min(capacity, min_capacity);
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max_capacity = max(capacity, max_capacity);
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}
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}
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} else {
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} else {
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/*
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/*
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@ -7620,12 +7623,14 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
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capacity += sgc->capacity;
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capacity += sgc->capacity;
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min_capacity = min(sgc->min_capacity, min_capacity);
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min_capacity = min(sgc->min_capacity, min_capacity);
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max_capacity = max(sgc->max_capacity, max_capacity);
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group = group->next;
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group = group->next;
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} while (group != child->groups);
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} while (group != child->groups);
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}
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}
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sdg->sgc->capacity = capacity;
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sdg->sgc->capacity = capacity;
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sdg->sgc->min_capacity = min_capacity;
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sdg->sgc->min_capacity = min_capacity;
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sdg->sgc->max_capacity = max_capacity;
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}
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}
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/*
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/*
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@ -7721,16 +7726,27 @@ group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs)
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}
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}
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/*
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/*
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* group_smaller_cpu_capacity: Returns true if sched_group sg has smaller
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* group_smaller_min_cpu_capacity: Returns true if sched_group sg has smaller
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* per-CPU capacity than sched_group ref.
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* per-CPU capacity than sched_group ref.
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*/
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*/
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static inline bool
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static inline bool
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group_smaller_cpu_capacity(struct sched_group *sg, struct sched_group *ref)
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group_smaller_min_cpu_capacity(struct sched_group *sg, struct sched_group *ref)
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{
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{
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return sg->sgc->min_capacity * capacity_margin <
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return sg->sgc->min_capacity * capacity_margin <
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ref->sgc->min_capacity * 1024;
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ref->sgc->min_capacity * 1024;
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}
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}
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/*
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* group_smaller_max_cpu_capacity: Returns true if sched_group sg has smaller
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* per-CPU capacity_orig than sched_group ref.
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*/
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static inline bool
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group_smaller_max_cpu_capacity(struct sched_group *sg, struct sched_group *ref)
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{
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return sg->sgc->max_capacity * capacity_margin <
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ref->sgc->max_capacity * 1024;
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}
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static inline enum
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static inline enum
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group_type group_classify(struct sched_group *group,
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group_type group_classify(struct sched_group *group,
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struct sg_lb_stats *sgs)
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struct sg_lb_stats *sgs)
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@ -7876,7 +7892,7 @@ static bool update_sd_pick_busiest(struct lb_env *env,
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* power/energy consequences are not considered.
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* power/energy consequences are not considered.
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*/
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*/
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if (sgs->sum_nr_running <= sgs->group_weight &&
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if (sgs->sum_nr_running <= sgs->group_weight &&
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group_smaller_cpu_capacity(sds->local, sg))
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group_smaller_min_cpu_capacity(sds->local, sg))
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return false;
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return false;
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asym_packing:
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asym_packing:
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@ -1197,6 +1197,7 @@ struct sched_group_capacity {
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*/
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*/
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unsigned long capacity;
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unsigned long capacity;
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unsigned long min_capacity; /* Min per-CPU capacity in group */
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unsigned long min_capacity; /* Min per-CPU capacity in group */
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unsigned long max_capacity; /* Max per-CPU capacity in group */
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unsigned long next_update;
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unsigned long next_update;
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int imbalance; /* XXX unrelated to capacity but shared group state */
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int imbalance; /* XXX unrelated to capacity but shared group state */
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@ -693,6 +693,7 @@ static void init_overlap_sched_group(struct sched_domain *sd,
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sg_span = sched_group_span(sg);
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sg_span = sched_group_span(sg);
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sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
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sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
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sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
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sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
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sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
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}
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}
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static int
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static int
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@ -852,6 +853,7 @@ static struct sched_group *get_group(int cpu, struct sd_data *sdd)
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sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg));
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sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg));
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sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
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sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
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sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
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return sg;
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return sg;
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}
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}
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