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sched: Introduce SCHED_POWER_SCALE to scale cpu_power calculations

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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: Nikhil Rao <ncrao@google.com>
Acked-by: Peter 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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Nikhil Rao
2011-05-18 10:09:39 -07:00
committed by Ingo Molnar
parent f05998d4b8
commit 1399fa7807
3 changed files with 37 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
include/linux/sched.h
View File

@@ -787,18 +787,21 @@ enum cpu_idle_type {
CPU_MAX_IDLE_TYPES CPU_MAX_IDLE_TYPES
}; };
/*
* sched-domains (multiprocessor balancing) declarations:
*/
/* /*
* Increase resolution of nice-level calculations: * Increase resolution of nice-level calculations:
*/ */
#define SCHED_LOAD_SHIFT 10 #define SCHED_LOAD_SHIFT 10
#define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT) #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 #ifdef CONFIG_SMP
#define SD_LOAD_BALANCE 0x0001 /* Do load balancing on this domain. */ #define SD_LOAD_BALANCE 0x0001 /* Do load balancing on this domain. */
#define SD_BALANCE_NEWIDLE 0x0002 /* Balance when about to become idle */ #define SD_BALANCE_NEWIDLE 0x0002 /* Balance when about to become idle */

4
kernel/sched.c
View File

@@ -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)); cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
printk(KERN_CONT " %s", str); 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)", printk(KERN_CONT " (cpu_power = %d)",
group->cpu_power); group->cpu_power);
} }
@@ -7905,7 +7905,7 @@ void __init sched_init(void)
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
rq->sd = NULL; rq->sd = NULL;
rq->rd = NULL; rq->rd = NULL;
rq->cpu_power = SCHED_LOAD_SCALE; rq->cpu_power = SCHED_POWER_SCALE;
rq->post_schedule = 0; rq->post_schedule = 0;
rq->active_balance = 0; rq->active_balance = 0;
rq->next_balance = jiffies; rq->next_balance = jiffies;

52
kernel/sched_fair.c
View File

@@ -1584,7 +1584,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
} }
/* Adjust by relative CPU power of the group */ /* 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) { if (local_group) {
this_load = avg_load; 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; 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) if (tmp->flags & SD_POWERSAVINGS_BALANCE)
nr_running /= 2; 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) 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) 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; available = total - rq->rt_avg;
} }
if (unlikely((s64)total < SCHED_LOAD_SCALE)) if (unlikely((s64)total < SCHED_POWER_SCALE))
total = SCHED_LOAD_SCALE; total = SCHED_POWER_SCALE;
total >>= SCHED_LOAD_SHIFT; total >>= SCHED_POWER_SHIFT;
return div_u64(available, total); 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) static void update_cpu_power(struct sched_domain *sd, int cpu)
{ {
unsigned long weight = sd->span_weight; unsigned long weight = sd->span_weight;
unsigned long power = SCHED_LOAD_SCALE; unsigned long power = SCHED_POWER_SCALE;
struct sched_group *sdg = sd->groups; struct sched_group *sdg = sd->groups;
if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
@@ -2627,7 +2627,7 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
else else
power *= default_scale_smt_power(sd, cpu); power *= default_scale_smt_power(sd, cpu);
power >>= SCHED_LOAD_SHIFT; power >>= SCHED_POWER_SHIFT;
} }
sdg->cpu_power_orig = power; sdg->cpu_power_orig = power;
@@ -2637,10 +2637,10 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
else else
power *= default_scale_freq_power(sd, cpu); power *= default_scale_freq_power(sd, cpu);
power >>= SCHED_LOAD_SHIFT; power >>= SCHED_POWER_SHIFT;
power *= scale_rt_power(cpu); power *= scale_rt_power(cpu);
power >>= SCHED_LOAD_SHIFT; power >>= SCHED_POWER_SHIFT;
if (!power) if (!power)
power = 1; power = 1;
@@ -2682,7 +2682,7 @@ static inline int
fix_small_capacity(struct sched_domain *sd, struct sched_group *group) 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)) if (!(sd->flags & SD_SHARE_CPUPOWER))
return 0; 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 */ /* 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 * 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) if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)
sgs->group_imb = 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) if (!sgs->group_capacity)
sgs->group_capacity = fix_small_capacity(sd, group); sgs->group_capacity = fix_small_capacity(sd, group);
sgs->group_weight = group->group_weight; sgs->group_weight = group->group_weight;
@@ -2961,7 +2962,7 @@ static int check_asym_packing(struct sched_domain *sd,
return 0; return 0;
*imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->cpu_power, *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->cpu_power,
SCHED_LOAD_SCALE); SCHED_POWER_SCALE);
return 1; return 1;
} }
@@ -2990,7 +2991,7 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds,
cpu_avg_load_per_task(this_cpu); cpu_avg_load_per_task(this_cpu);
scaled_busy_load_per_task = sds->busiest_load_per_task 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; scaled_busy_load_per_task /= sds->busiest->cpu_power;
if (sds->max_load - sds->this_load + scaled_busy_load_per_task >= 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); 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); 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 */ /* 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; sds->busiest->cpu_power;
if (sds->max_load > tmp) if (sds->max_load > tmp)
pwr_move += sds->busiest->cpu_power * 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 */ /* 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) sds->busiest_load_per_task * SCHED_POWER_SCALE)
tmp = (sds->max_load * sds->busiest->cpu_power) / tmp = (sds->max_load * sds->busiest->cpu_power) /
sds->this->cpu_power; sds->this->cpu_power;
else else
tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
sds->this->cpu_power; sds->this->cpu_power;
pwr_move += sds->this->cpu_power * pwr_move += sds->this->cpu_power *
min(sds->this_load_per_task, sds->this_load + tmp); 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 */ /* Move if we gain throughput */
if (pwr_move > pwr_now) 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 - load_above_capacity = (sds->busiest_nr_running -
sds->busiest_group_capacity); 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; 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 */ /* How much load to actually move to equalise the imbalance */
*imbalance = min(max_pull * sds->busiest->cpu_power, *imbalance = min(max_pull * sds->busiest->cpu_power,
(sds->avg_load - sds->this_load) * sds->this->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 * 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) if (!sds.busiest || sds.busiest_nr_running == 0)
goto out_balanced; 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 * 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)) { for_each_cpu(i, sched_group_cpus(group)) {
unsigned long power = power_of(i); 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; unsigned long wl;
if (!capacity) 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 * the load can be moved away from the cpu that is potentially
* running at a lower capacity. * running at a lower capacity.
*/ */
wl = (wl * SCHED_LOAD_SCALE) / power; wl = (wl * SCHED_POWER_SCALE) / power;
if (wl > max_load) { if (wl > max_load) {
max_load = wl; max_load = wl;