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Message-ID: <tip-381be78fdc829a22f6327a0ed09f54b6270a976d@git.kernel.org>
Date: Wed, 25 Mar 2009 09:46:17 GMT
From: Gautham R Shenoy <ego@...ibm.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, ego@...ibm.com, hpa@...or.com,
mingo@...hat.com, a.p.zijlstra@...llo.nl,
dhaval@...ux.vnet.ibm.com, balbir@...ibm.com,
bharata@...ux.vnet.ibm.com, suresh.b.siddha@...el.com,
tglx@...utronix.de, mingo@...e.hu, nickpiggin@...oo.com.au
Subject: [tip:sched/balancing] sched: Define structure to store the sched_group statistics for fbg()
Commit-ID: 381be78fdc829a22f6327a0ed09f54b6270a976d
Gitweb: http://git.kernel.org/tip/381be78fdc829a22f6327a0ed09f54b6270a976d
Author: Gautham R Shenoy <ego@...ibm.com>
AuthorDate: Wed, 25 Mar 2009 14:43:46 +0530
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Wed, 25 Mar 2009 10:30:45 +0100
sched: Define structure to store the sched_group statistics for fbg()
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@...ux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@...ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Suresh Siddha <suresh.b.siddha@...el.com>
Cc: "Balbir Singh" <balbir@...ibm.com>
Cc: Nick Piggin <nickpiggin@...oo.com.au>
Cc: "Dhaval Giani" <dhaval@...ux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@...ux.vnet.ibm.com>
LKML-Reference: <20090325091345.13992.20099.stgit@...ia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
kernel/sched.c | 79 ++++++++++++++++++++++++++++++++-----------------------
1 files changed, 46 insertions(+), 33 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index f87adbe..109db12 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3192,6 +3192,18 @@ 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
--
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