From: Peter Zijlstra Date: Tue, 1 Sep 2009 08:34:39 +0000 (+0200) Subject: sched: Remove reciprocal for cpu_power X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=18a3885fc1ffa92c2212ff0afdf033403d5b0fa0;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git sched: Remove reciprocal for cpu_power Its a source of fail, also, now that cpu_power is dynamical, its a waste of time. before: -0 [000] 132.877936: find_busiest_group: avg_load: 0 group_load: 8241 power: 1 after: bash-1689 [001] 137.862151: find_busiest_group: avg_load: 10636288 group_load: 10387 power: 1 [ v2: build fix from From: Andreas Herrmann ] Signed-off-by: Peter Zijlstra Tested-by: Andreas Herrmann Acked-by: Andreas Herrmann Acked-by: Gautham R Shenoy Cc: Balbir Singh LKML-Reference: <20090901083826.425896304@chello.nl> Signed-off-by: Ingo Molnar --- diff --git a/include/linux/sched.h b/include/linux/sched.h index c67ddf309c84..3b7f43e3b736 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -860,15 +860,9 @@ struct sched_group { /* * CPU power of this group, SCHED_LOAD_SCALE being max power for a - * single CPU. This is read only (except for setup, hotplug CPU). - * Note : Never change cpu_power without recompute its reciprocal + * single CPU. */ - unsigned int __cpu_power; - /* - * reciprocal value of cpu_power to avoid expensive divides - * (see include/linux/reciprocal_div.h) - */ - u32 reciprocal_cpu_power; + unsigned int cpu_power; /* * The CPUs this group covers. diff --git a/kernel/sched.c b/kernel/sched.c index e1ebf9b00f5d..b53785346850 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -64,7 +64,6 @@ #include #include #include -#include #include #include #include @@ -120,30 +119,8 @@ */ #define RUNTIME_INF ((u64)~0ULL) -#ifdef CONFIG_SMP - static void double_rq_lock(struct rq *rq1, struct rq *rq2); -/* - * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) - * Since cpu_power is a 'constant', we can use a reciprocal divide. - */ -static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) -{ - return reciprocal_divide(load, sg->reciprocal_cpu_power); -} - -/* - * Each time a sched group cpu_power is changed, - * we must compute its reciprocal value - */ -static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) -{ - sg->__cpu_power += val; - sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); -} -#endif - static inline int rt_policy(int policy) { if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR)) @@ -2335,8 +2312,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) } /* Adjust by relative CPU power of the group */ - avg_load = sg_div_cpu_power(group, - avg_load * SCHED_LOAD_SCALE); + avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; if (local_group) { this_load = avg_load; @@ -3768,7 +3744,6 @@ static void update_cpu_power(struct sched_domain *sd, int cpu) unsigned long weight = cpumask_weight(sched_domain_span(sd)); unsigned long power = SCHED_LOAD_SCALE; struct sched_group *sdg = sd->groups; - unsigned long old = sdg->__cpu_power; /* here we could scale based on cpufreq */ @@ -3783,33 +3758,26 @@ static void update_cpu_power(struct sched_domain *sd, int cpu) if (!power) power = 1; - if (power != old) { - sdg->__cpu_power = power; - sdg->reciprocal_cpu_power = reciprocal_value(power); - } + sdg->cpu_power = power; } static void update_group_power(struct sched_domain *sd, int cpu) { struct sched_domain *child = sd->child; struct sched_group *group, *sdg = sd->groups; - unsigned long power = sdg->__cpu_power; if (!child) { update_cpu_power(sd, cpu); return; } - sdg->__cpu_power = 0; + sdg->cpu_power = 0; group = child->groups; do { - sdg->__cpu_power += group->__cpu_power; + sdg->cpu_power += group->cpu_power; group = group->next; } while (group != child->groups); - - if (power != sdg->__cpu_power) - sdg->reciprocal_cpu_power = reciprocal_value(sdg->__cpu_power); } /** @@ -3889,8 +3857,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, } /* Adjust by relative CPU power of the group */ - sgs->avg_load = sg_div_cpu_power(group, - sgs->group_load * SCHED_LOAD_SCALE); + sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; /* @@ -3902,14 +3869,14 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, * normalized nr_running number somewhere that negates * the hierarchy? */ - avg_load_per_task = sg_div_cpu_power(group, - sum_avg_load_per_task * SCHED_LOAD_SCALE); + avg_load_per_task = (sum_avg_load_per_task * SCHED_LOAD_SCALE) / + group->cpu_power; if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) sgs->group_imb = 1; sgs->group_capacity = - DIV_ROUND_CLOSEST(group->__cpu_power, SCHED_LOAD_SCALE); + DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE); } /** @@ -3951,7 +3918,7 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, return; sds->total_load += sgs.group_load; - sds->total_pwr += group->__cpu_power; + sds->total_pwr += group->cpu_power; /* * In case the child domain prefers tasks go to siblings @@ -4016,28 +3983,28 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, * moving them. */ - pwr_now += sds->busiest->__cpu_power * + pwr_now += sds->busiest->cpu_power * min(sds->busiest_load_per_task, sds->max_load); - pwr_now += sds->this->__cpu_power * + pwr_now += sds->this->cpu_power * min(sds->this_load_per_task, sds->this_load); pwr_now /= SCHED_LOAD_SCALE; /* Amount of load we'd subtract */ - tmp = sg_div_cpu_power(sds->busiest, - sds->busiest_load_per_task * SCHED_LOAD_SCALE); + tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / + sds->busiest->cpu_power; if (sds->max_load > tmp) - pwr_move += sds->busiest->__cpu_power * + pwr_move += sds->busiest->cpu_power * min(sds->busiest_load_per_task, sds->max_load - tmp); /* Amount of load we'd add */ - if (sds->max_load * sds->busiest->__cpu_power < + if (sds->max_load * sds->busiest->cpu_power < sds->busiest_load_per_task * SCHED_LOAD_SCALE) - tmp = sg_div_cpu_power(sds->this, - sds->max_load * sds->busiest->__cpu_power); + tmp = (sds->max_load * sds->busiest->cpu_power) / + sds->this->cpu_power; else - tmp = sg_div_cpu_power(sds->this, - sds->busiest_load_per_task * SCHED_LOAD_SCALE); - pwr_move += sds->this->__cpu_power * + tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / + sds->this->cpu_power; + pwr_move += sds->this->cpu_power * min(sds->this_load_per_task, sds->this_load + tmp); pwr_move /= SCHED_LOAD_SCALE; @@ -4072,8 +4039,8 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, sds->max_load - sds->busiest_load_per_task); /* How much load to actually move to equalise the imbalance */ - *imbalance = min(max_pull * sds->busiest->__cpu_power, - (sds->avg_load - sds->this_load) * sds->this->__cpu_power) + *imbalance = min(max_pull * sds->busiest->cpu_power, + (sds->avg_load - sds->this_load) * sds->this->cpu_power) / SCHED_LOAD_SCALE; /* @@ -4208,7 +4175,7 @@ static unsigned long power_of(int cpu) if (!group) return SCHED_LOAD_SCALE; - return group->__cpu_power; + return group->cpu_power; } /* @@ -7922,7 +7889,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, break; } - if (!group->__cpu_power) { + if (!group->cpu_power) { printk(KERN_CONT "\n"); printk(KERN_ERR "ERROR: domain->cpu_power not " "set\n"); @@ -7946,9 +7913,9 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); printk(KERN_CONT " %s", str); - if (group->__cpu_power != SCHED_LOAD_SCALE) { - printk(KERN_CONT " (__cpu_power = %d)", - group->__cpu_power); + if (group->cpu_power != SCHED_LOAD_SCALE) { + printk(KERN_CONT " (cpu_power = %d)", + group->cpu_power); } group = group->next; @@ -8233,7 +8200,7 @@ init_sched_build_groups(const struct cpumask *span, continue; cpumask_clear(sched_group_cpus(sg)); - sg->__cpu_power = 0; + sg->cpu_power = 0; for_each_cpu(j, span) { if (group_fn(j, cpu_map, NULL, tmpmask) != group) @@ -8491,7 +8458,7 @@ static void init_numa_sched_groups_power(struct sched_group *group_head) continue; } - sg_inc_cpu_power(sg, sd->groups->__cpu_power); + sg->cpu_power += sd->groups->cpu_power; } sg = sg->next; } while (sg != group_head); @@ -8528,7 +8495,7 @@ static int build_numa_sched_groups(struct s_data *d, sd->groups = sg; } - sg->__cpu_power = 0; + sg->cpu_power = 0; cpumask_copy(sched_group_cpus(sg), d->nodemask); sg->next = sg; cpumask_or(d->covered, d->covered, d->nodemask); @@ -8551,7 +8518,7 @@ static int build_numa_sched_groups(struct s_data *d, "Can not alloc domain group for node %d\n", j); return -ENOMEM; } - sg->__cpu_power = 0; + sg->cpu_power = 0; cpumask_copy(sched_group_cpus(sg), d->tmpmask); sg->next = prev->next; cpumask_or(d->covered, d->covered, d->tmpmask); @@ -8629,7 +8596,7 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) child = sd->child; - sd->groups->__cpu_power = 0; + sd->groups->cpu_power = 0; if (!child) { power = SCHED_LOAD_SCALE; @@ -8645,7 +8612,7 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) power /= weight; power >>= SCHED_LOAD_SHIFT; } - sg_inc_cpu_power(sd->groups, power); + sd->groups->cpu_power += power; return; } @@ -8654,7 +8621,7 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) */ group = child->groups; do { - sg_inc_cpu_power(sd->groups, group->__cpu_power); + sd->groups->cpu_power += group->cpu_power; group = group->next; } while (group != child->groups); }