Messages in this thread | | | Date | Tue, 12 Jul 2022 11:48:43 +0100 | From | Qais Yousef <> | Subject | Re: [PATCH 2/7] sched/uclamp: Make task_fits_capacity() use util_fits_cpu() |
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On 07/11/22 15:09, Vincent Guittot wrote: > On Wed, 29 Jun 2022 at 21:48, Qais Yousef <qais.yousef@arm.com> wrote:
[...]
> > @@ -8502,15 +8504,16 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) > > trace_sched_cpu_capacity_tp(cpu_rq(cpu)); > > > > sdg->sgc->capacity = capacity; > > - sdg->sgc->min_capacity = capacity; > > - sdg->sgc->max_capacity = capacity; > > + sdg->sgc->min_capacity_cpu = cpu; > > + sdg->sgc->max_capacity_cpu = cpu; > > you make these fields useless. There is only one cpu per sched_group > at this level so you don't need to save the twice cpu number of the > nly cpu of this group
Ah, so we can use group->asym_prefer_cpu then?
I think I got confused and thought we could cover multiple capacity levels there.
> > } > > > > void update_group_capacity(struct sched_domain *sd, int cpu) > > { > > - struct sched_domain *child = sd->child; > > struct sched_group *group, *sdg = sd->groups; > > - unsigned long capacity, min_capacity, max_capacity; > > + struct sched_domain *child = sd->child; > > + int min_capacity_cpu, max_capacity_cpu; > > + unsigned long capacity; > > unsigned long interval; > > > > interval = msecs_to_jiffies(sd->balance_interval); > > @@ -8523,8 +8526,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu) > > } > > > > capacity = 0; > > - min_capacity = ULONG_MAX; > > - max_capacity = 0; > > + min_capacity_cpu = max_capacity_cpu = cpu; > > > > if (child->flags & SD_OVERLAP) { > > /* > > @@ -8536,29 +8538,44 @@ void update_group_capacity(struct sched_domain *sd, int cpu) > > unsigned long cpu_cap = capacity_of(cpu); > > > > capacity += cpu_cap; > > - min_capacity = min(cpu_cap, min_capacity); > > - max_capacity = max(cpu_cap, max_capacity); > > + if (cpu_cap < capacity_of(min_capacity_cpu)) > > + min_capacity_cpu = cpu; > > + > > + if (cpu_cap > capacity_of(max_capacity_cpu)) > > + max_capacity_cpu = cpu; > > } > > } else { > > /* > > * !SD_OVERLAP domains can assume that child groups > > * span the current group. > > */ > > + unsigned long min_capacity = ULONG_MAX; > > + unsigned long max_capacity = 0; > > > > group = child->groups; > > do { > > struct sched_group_capacity *sgc = group->sgc; > > + unsigned long cpu_cap_min = capacity_of(sgc->min_capacity_cpu); > > + unsigned long cpu_cap_max = capacity_of(sgc->max_capacity_cpu); > > By replacing sgc->min_capacity with sgc->min_capacity_cpu, the > min_capacity is no more stable and can become > max_capacity
Right.
> > > > > capacity += sgc->capacity; > > - min_capacity = min(sgc->min_capacity, min_capacity); > > - max_capacity = max(sgc->max_capacity, max_capacity); > > + if (cpu_cap_min < min_capacity) { > > + min_capacity = cpu_cap_min; > > + min_capacity_cpu = sgc->min_capacity_cpu; > > + } > > + > > + if (cpu_cap_max > max_capacity) { > > + max_capacity = cpu_cap_max; > > + max_capacity_cpu = sgc->max_capacity_cpu; > > + } > > + > > group = group->next; > > } while (group != child->groups); > > } > > > > sdg->sgc->capacity = capacity; > > - sdg->sgc->min_capacity = min_capacity; > > - sdg->sgc->max_capacity = max_capacity; > > + sdg->sgc->min_capacity_cpu = min_capacity_cpu; > > + sdg->sgc->max_capacity_cpu = max_capacity_cpu; > > } > > > > /* > > @@ -8902,7 +8919,7 @@ static bool update_sd_pick_busiest(struct lb_env *env, > > * internally or be covered by avg_load imbalance (eventually). > > */ > > if (sgs->group_type == group_misfit_task && > > - (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) || > > + (!capacity_greater(env->dst_cpu, sg->sgc->max_capacity_cpu) || > > sds->local_stat.group_type != group_has_spare)) > > return false; > > > > @@ -8986,7 +9003,7 @@ static bool update_sd_pick_busiest(struct lb_env *env, > > */ > > if ((env->sd->flags & SD_ASYM_CPUCAPACITY) && > > (sgs->group_type <= group_fully_busy) && > > - (capacity_greater(sg->sgc->min_capacity, capacity_of(env->dst_cpu)))) > > + (capacity_greater(sg->sgc->min_capacity_cpu, env->dst_cpu))) > > return false; > > > > return true; > > @@ -9108,7 +9125,7 @@ static inline void update_sg_wakeup_stats(struct sched_domain *sd, > > > > /* Check if task fits in the group */ > > if (sd->flags & SD_ASYM_CPUCAPACITY && > > - !task_fits_capacity(p, group->sgc->max_capacity)) { > > + !task_fits_cpu(p, group->sgc->max_capacity_cpu)) { > > All the changes and added complexity above for this line. Can't you > find another way ?
You're right, I might have got carried away trying to keep the logic the same.
Can we use group->asym_prefer_cpu or pick a cpu from group->sgc->cpumask instead?
I'll dig more into it anyway and try to come up with simpler alternative.
Thanks!
-- Qais Yousef
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