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Commit 1399fa78 authored by Nikhil Rao's avatar Nikhil Rao Committed by Ingo Molnar
Browse files

sched: Introduce SCHED_POWER_SCALE to scale cpu_power calculations 



SCHED_LOAD_SCALE is used to increase nice resolution and to
scale cpu_power calculations in the scheduler. This patch
introduces SCHED_POWER_SCALE and converts all uses of
SCHED_LOAD_SCALE for scaling cpu_power to use SCHED_POWER_SCALE
instead.

This is a preparatory patch for increasing the resolution of
SCHED_LOAD_SCALE, and there is no need to increase resolution
for cpu_power calculations.

Signed-off-by: default avatarNikhil Rao <ncrao@google.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1305738580-9924-3-git-send-email-ncrao@google.com


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f05998d4

include/linux/sched.h

+8 −5
Original line number Diff line number Diff line
@@ -787,18 +787,21 @@ enum cpu_idle_type { 
	CPU_MAX_IDLE_TYPES

};



/*

 * sched-domains (multiprocessor balancing) declarations:

 */



/*

 * Increase resolution of nice-level calculations:

 */

#define SCHED_LOAD_SHIFT	10

#define SCHED_LOAD_SCALE	(1L << SCHED_LOAD_SHIFT)



#define SCHED_LOAD_SCALE_FUZZ	SCHED_LOAD_SCALE

/*

 * Increase resolution of cpu_power calculations

 */

#define SCHED_POWER_SHIFT	10

#define SCHED_POWER_SCALE	(1L << SCHED_POWER_SHIFT)



/*

 * sched-domains (multiprocessor balancing) declarations:

 */

#ifdef CONFIG_SMP

#define SD_LOAD_BALANCE		0x0001	/* Do load balancing on this domain. */

#define SD_BALANCE_NEWIDLE	0x0002	/* Balance when about to become idle */

kernel/sched.c

+2 −2
Original line number Diff line number Diff line
@@ -6530,7 +6530,7 @@ 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) {

		if (group->cpu_power != SCHED_POWER_SCALE) {

			printk(KERN_CONT " (cpu_power = %d)",

				group->cpu_power);

		}
@@ -7905,7 +7905,7 @@ void __init sched_init(void) 
#ifdef CONFIG_SMP

		rq->sd = NULL;

		rq->rd = NULL;

		rq->cpu_power = SCHED_LOAD_SCALE;

		rq->cpu_power = SCHED_POWER_SCALE;

		rq->post_schedule = 0;

		rq->active_balance = 0;

		rq->next_balance = jiffies;

kernel/sched_fair.c

+27 −25
Original line number Diff line number Diff line
@@ -1584,7 +1584,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, 
		}



		/* Adjust by relative CPU power of the group */

		avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;

		avg_load = (avg_load * SCHED_POWER_SCALE) / group->cpu_power;



		if (local_group) {

			this_load = avg_load;
@@ -1722,7 +1722,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) 
				nr_running += cpu_rq(i)->cfs.nr_running;

			}



			capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE);

			capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);



			if (tmp->flags & SD_POWERSAVINGS_BALANCE)

				nr_running /= 2;
@@ -2570,7 +2570,7 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, 


unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)

{

	return SCHED_LOAD_SCALE;

	return SCHED_POWER_SCALE;

}



unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
@@ -2607,10 +2607,10 @@ unsigned long scale_rt_power(int cpu) 
		available = total - rq->rt_avg;

	}



	if (unlikely((s64)total < SCHED_LOAD_SCALE))

		total = SCHED_LOAD_SCALE;

	if (unlikely((s64)total < SCHED_POWER_SCALE))

		total = SCHED_POWER_SCALE;



	total >>= SCHED_LOAD_SHIFT;

	total >>= SCHED_POWER_SHIFT;



	return div_u64(available, total);

}
@@ -2618,7 +2618,7 @@ unsigned long scale_rt_power(int cpu) 
static void update_cpu_power(struct sched_domain *sd, int cpu)

{

	unsigned long weight = sd->span_weight;

	unsigned long power = SCHED_LOAD_SCALE;

	unsigned long power = SCHED_POWER_SCALE;

	struct sched_group *sdg = sd->groups;



	if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
@@ -2627,7 +2627,7 @@ static void update_cpu_power(struct sched_domain *sd, int cpu) 
		else

			power *= default_scale_smt_power(sd, cpu);



		power >>= SCHED_LOAD_SHIFT;

		power >>= SCHED_POWER_SHIFT;

	}



	sdg->cpu_power_orig = power;
@@ -2637,10 +2637,10 @@ static void update_cpu_power(struct sched_domain *sd, int cpu) 
	else

		power *= default_scale_freq_power(sd, cpu);



	power >>= SCHED_LOAD_SHIFT;

	power >>= SCHED_POWER_SHIFT;



	power *= scale_rt_power(cpu);

	power >>= SCHED_LOAD_SHIFT;

	power >>= SCHED_POWER_SHIFT;



	if (!power)

		power = 1;
@@ -2682,7 +2682,7 @@ static inline int 
fix_small_capacity(struct sched_domain *sd, struct sched_group *group)

{

	/*

	 * Only siblings can have significantly less than SCHED_LOAD_SCALE

	 * Only siblings can have significantly less than SCHED_POWER_SCALE

	 */

	if (!(sd->flags & SD_SHARE_CPUPOWER))

		return 0;
@@ -2770,7 +2770,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, 
	}



	/* Adjust by relative CPU power of the group */

	sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power;

	sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / group->cpu_power;



	/*

	 * Consider the group unbalanced when the imbalance is larger
@@ -2787,7 +2787,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, 
	if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)

		sgs->group_imb = 1;



	sgs->group_capacity = DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE);

	sgs->group_capacity = DIV_ROUND_CLOSEST(group->cpu_power,

						SCHED_POWER_SCALE);

	if (!sgs->group_capacity)

		sgs->group_capacity = fix_small_capacity(sd, group);

	sgs->group_weight = group->group_weight;
@@ -2961,7 +2962,7 @@ static int check_asym_packing(struct sched_domain *sd, 
		return 0;



	*imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->cpu_power,

				       SCHED_LOAD_SCALE);

				       SCHED_POWER_SCALE);

	return 1;

}
@@ -2990,7 +2991,7 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, 
			cpu_avg_load_per_task(this_cpu);



	scaled_busy_load_per_task = sds->busiest_load_per_task

						 * SCHED_LOAD_SCALE;

					 * SCHED_POWER_SCALE;

	scaled_busy_load_per_task /= sds->busiest->cpu_power;



	if (sds->max_load - sds->this_load + scaled_busy_load_per_task >=
@@ -3009,10 +3010,10 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, 
			min(sds->busiest_load_per_task, sds->max_load);

	pwr_now += sds->this->cpu_power *

			min(sds->this_load_per_task, sds->this_load);

	pwr_now /= SCHED_LOAD_SCALE;

	pwr_now /= SCHED_POWER_SCALE;



	/* Amount of load we'd subtract */

	tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) /

	tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /

		sds->busiest->cpu_power;

	if (sds->max_load > tmp)

		pwr_move += sds->busiest->cpu_power *
@@ -3020,15 +3021,15 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, 


	/* Amount of load we'd add */

	if (sds->max_load * sds->busiest->cpu_power <

		sds->busiest_load_per_task * SCHED_LOAD_SCALE)

		sds->busiest_load_per_task * SCHED_POWER_SCALE)

		tmp = (sds->max_load * sds->busiest->cpu_power) /

			sds->this->cpu_power;

	else

		tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) /

		tmp = (sds->busiest_load_per_task * SCHED_POWER_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;

	pwr_move /= SCHED_POWER_SCALE;



	/* Move if we gain throughput */

	if (pwr_move > pwr_now)
@@ -3070,7 +3071,7 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, 
		load_above_capacity = (sds->busiest_nr_running -

						sds->busiest_group_capacity);



		load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_LOAD_SCALE);

		load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE);



		load_above_capacity /= sds->busiest->cpu_power;

	}
@@ -3090,7 +3091,7 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, 
	/* 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)

			/ SCHED_LOAD_SCALE;

			/ SCHED_POWER_SCALE;



	/*

	 * if *imbalance is less than the average load per runnable task
@@ -3159,7 +3160,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
	if (!sds.busiest || sds.busiest_nr_running == 0)

		goto out_balanced;



	sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;

	sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr;



	/*

	 * If the busiest group is imbalanced the below checks don't
@@ -3238,7 +3239,8 @@ find_busiest_queue(struct sched_domain *sd, struct sched_group *group, 


	for_each_cpu(i, sched_group_cpus(group)) {

		unsigned long power = power_of(i);

		unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE);

		unsigned long capacity = DIV_ROUND_CLOSEST(power,

							   SCHED_POWER_SCALE);

		unsigned long wl;



		if (!capacity)
@@ -3263,7 +3265,7 @@ find_busiest_queue(struct sched_domain *sd, struct sched_group *group, 
		 * the load can be moved away from the cpu that is potentially

		 * running at a lower capacity.

		 */

		wl = (wl * SCHED_LOAD_SCALE) / power;

		wl = (wl * SCHED_POWER_SCALE) / power;



		if (wl > max_load) {

			max_load = wl;