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sched: Define structure to store the sched_group statistics for fbg()

Browse source 
Impact: cleanup

Currently a whole bunch of variables are used to store the
various statistics pertaining to the groups we iterate over
in find_busiest_group().

Group them together in a single data structure and add
appropriate comments.

This will be useful later on when we create helper functions
to calculate the sched_group statistics.

Credit: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Balbir Singh" <balbir@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Dhaval Giani" <dhaval@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <20090325091345.13992.20099.stgit@sofia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Gautham R Shenoy 2009-03-25 14:43:46 +05:30 committed by Ingo Molnar
parent 6dfdb06290
commit 381be78fdc
1 changed files with 46 additions and 33 deletions
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79
kernel/sched.c
View file

@ -3191,6 +3191,18 @@ static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
}
/********** Helpers for find_busiest_group ************************/
/**
* sg_lb_stats - stats of a sched_group required for load_balancing
*/
struct sg_lb_stats {
unsigned long avg_load; /*Avg load across the CPUs of the group */
unsigned long group_load; /* Total load over the CPUs of the group */
unsigned long sum_nr_running; /* Nr tasks running in the group */
unsigned long sum_weighted_load; /* Weighted load of group's tasks */
unsigned long group_capacity;
int group_imb; /* Is there an imbalance in the group ? */
};
/**
* group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
* @group: The group whose first cpu is to be returned.
@ -3257,23 +3269,22 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
load_idx = get_sd_load_idx(sd, idle);
do {
unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
struct sg_lb_stats sgs;
unsigned long load, max_cpu_load, min_cpu_load;
int local_group;
int i;
int __group_imb = 0;
unsigned int balance_cpu = -1, first_idle_cpu = 0;
unsigned long sum_nr_running, sum_weighted_load;
unsigned long sum_avg_load_per_task;
unsigned long avg_load_per_task;
local_group = cpumask_test_cpu(this_cpu,
sched_group_cpus(group));
memset(&sgs, 0, sizeof(sgs));
if (local_group)
balance_cpu = group_first_cpu(group);
/* Tally up the load of all CPUs in the group */
sum_weighted_load = sum_nr_running = avg_load = 0;
sum_avg_load_per_task = avg_load_per_task = 0;
max_cpu_load = 0;
@ -3301,9 +3312,9 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
min_cpu_load = load;
}
avg_load += load;
sum_nr_running += rq->nr_running;
sum_weighted_load += weighted_cpuload(i);
sgs.group_load += load;
sgs.sum_nr_running += rq->nr_running;
sgs.sum_weighted_load += weighted_cpuload(i);
sum_avg_load_per_task += cpu_avg_load_per_task(i);
}
@ -3320,12 +3331,12 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
goto ret;
}
total_load += avg_load;
total_load += sgs.group_load;
total_pwr += group->__cpu_power;
/* Adjust by relative CPU power of the group */
avg_load = sg_div_cpu_power(group,
avg_load * SCHED_LOAD_SCALE);
sgs.avg_load = sg_div_cpu_power(group,
sgs.group_load * SCHED_LOAD_SCALE);
/*
@ -3341,22 +3352,23 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
sum_avg_load_per_task * SCHED_LOAD_SCALE);
if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
__group_imb = 1;
sgs.group_imb = 1;
group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
sgs.group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
if (local_group) {
this_load = avg_load;
this_load = sgs.avg_load;
this = group;
this_nr_running = sum_nr_running;
this_load_per_task = sum_weighted_load;
} else if (avg_load > max_load &&
(sum_nr_running > group_capacity || __group_imb)) {
max_load = avg_load;
this_nr_running = sgs.sum_nr_running;
this_load_per_task = sgs.sum_weighted_load;
} else if (sgs.avg_load > max_load &&
(sgs.sum_nr_running > sgs.group_capacity ||
sgs.group_imb)) {
max_load = sgs.avg_load;
busiest = group;
busiest_nr_running = sum_nr_running;
busiest_load_per_task = sum_weighted_load;
group_imb = __group_imb;
busiest_nr_running = sgs.sum_nr_running;
busiest_load_per_task = sgs.sum_weighted_load;
group_imb = sgs.group_imb;
}
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
@ -3372,7 +3384,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
* If the local group is idle or completely loaded
* no need to do power savings balance at this domain
*/
if (local_group && (this_nr_running >= group_capacity ||
if (local_group && (this_nr_running >= sgs.group_capacity ||
!this_nr_running))
power_savings_balance = 0;
@ -3380,8 +3392,9 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
* If a group is already running at full capacity or idle,
* don't include that group in power savings calculations
*/
if (!power_savings_balance || sum_nr_running >= group_capacity
|| !sum_nr_running)
if (!power_savings_balance ||
sgs.sum_nr_running >= sgs.group_capacity ||
!sgs.sum_nr_running)
goto group_next;
/*
@ -3389,13 +3402,13 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
* This is the group from where we need to pick up the load
* for saving power
*/
if ((sum_nr_running < min_nr_running) ||
(sum_nr_running == min_nr_running &&
if ((sgs.sum_nr_running < min_nr_running) ||
(sgs.sum_nr_running == min_nr_running &&
group_first_cpu(group) > group_first_cpu(group_min))) {
group_min = group;
min_nr_running = sum_nr_running;
min_load_per_task = sum_weighted_load /
sum_nr_running;
min_nr_running = sgs.sum_nr_running;
min_load_per_task = sgs.sum_weighted_load /
sgs.sum_nr_running;
}
/*
@ -3403,14 +3416,14 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
* capacity but still has some space to pick up some load
* from other group and save more power
*/
if (sum_nr_running > group_capacity - 1)
if (sgs.sum_nr_running > sgs.group_capacity - 1)
goto group_next;
if (sum_nr_running > leader_nr_running ||
(sum_nr_running == leader_nr_running &&
if (sgs.sum_nr_running > leader_nr_running ||
(sgs.sum_nr_running == leader_nr_running &&
group_first_cpu(group) < group_first_cpu(group_leader))) {
group_leader = group;
leader_nr_running = sum_nr_running;
leader_nr_running = sgs.sum_nr_running;
}
group_next:
#endif