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Date: Wed, 25 Mar 2009 09:46:32 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_domain statistics for fbg()
Commit-ID: 222d656dea57e4e084fbd1e9383e6fed2ca9fa61
Gitweb: http://git.kernel.org/tip/222d656dea57e4e084fbd1e9383e6fed2ca9fa61
Author: Gautham R Shenoy <ego@...ibm.com>
AuthorDate: Wed, 25 Mar 2009 14:43:56 +0530
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Wed, 25 Mar 2009 10:30:46 +0100
sched: Define structure to store the sched_domain statistics for fbg()
Impact: cleanup
Currently we use a lot of local variables in find_busiest_group()
to capture the various statistics related to the sched_domain.
Group them together into a single data structure.
This will help us to offload the job of updating the sched_domain
statistics to a helper function.
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: <20090325091356.13992.25970.stgit@...ia.in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
kernel/sched.c | 207 +++++++++++++++++++++++++++++++++-----------------------
1 files changed, 121 insertions(+), 86 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 1893d55..8198dbe 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3190,6 +3190,37 @@ static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
return 0;
}
/********** Helpers for find_busiest_group ************************/
+/**
+ * sd_lb_stats - Structure to store the statistics of a sched_domain
+ * during load balancing.
+ */
+struct sd_lb_stats {
+ struct sched_group *busiest; /* Busiest group in this sd */
+ struct sched_group *this; /* Local group in this sd */
+ unsigned long total_load; /* Total load of all groups in sd */
+ unsigned long total_pwr; /* Total power of all groups in sd */
+ unsigned long avg_load; /* Average load across all groups in sd */
+
+ /** Statistics of this group */
+ unsigned long this_load;
+ unsigned long this_load_per_task;
+ unsigned long this_nr_running;
+
+ /* Statistics of the busiest group */
+ unsigned long max_load;
+ unsigned long busiest_load_per_task;
+ unsigned long busiest_nr_running;
+
+ int group_imb; /* Is there imbalance in this sd */
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+ int power_savings_balance; /* Is powersave balance needed for this sd */
+ struct sched_group *group_min; /* Least loaded group in sd */
+ struct sched_group *group_leader; /* Group which relieves group_min */
+ unsigned long min_load_per_task; /* load_per_task in group_min */
+ unsigned long leader_nr_running; /* Nr running of group_leader */
+ unsigned long min_nr_running; /* Nr running of group_min */
+#endif
+};
/**
* sg_lb_stats - stats of a sched_group required for load_balancing
@@ -3346,23 +3377,16 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
unsigned long *imbalance, enum cpu_idle_type idle,
int *sd_idle, const struct cpumask *cpus, int *balance)
{
- struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
- unsigned long max_load, avg_load, total_load, this_load, total_pwr;
+ struct sd_lb_stats sds;
+ struct sched_group *group = sd->groups;
unsigned long max_pull;
- unsigned long busiest_load_per_task, busiest_nr_running;
- unsigned long this_load_per_task, this_nr_running;
- int load_idx, group_imb = 0;
+ int load_idx;
+
+ memset(&sds, 0, sizeof(sds));
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
- int power_savings_balance = 1;
- unsigned long leader_nr_running = 0, min_load_per_task = 0;
- unsigned long min_nr_running = ULONG_MAX;
- struct sched_group *group_min = NULL, *group_leader = NULL;
+ sds.power_savings_balance = 1;
+ sds.min_nr_running = ULONG_MAX;
#endif
-
- max_load = this_load = total_load = total_pwr = 0;
- busiest_load_per_task = busiest_nr_running = 0;
- this_load_per_task = this_nr_running = 0;
-
load_idx = get_sd_load_idx(sd, idle);
do {
@@ -3378,22 +3402,22 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
if (balance && !(*balance))
goto ret;
- total_load += sgs.group_load;
- total_pwr += group->__cpu_power;
+ sds.total_load += sgs.group_load;
+ sds.total_pwr += group->__cpu_power;
if (local_group) {
- this_load = sgs.avg_load;
- this = group;
- this_nr_running = sgs.sum_nr_running;
- this_load_per_task = sgs.sum_weighted_load;
- } else if (sgs.avg_load > max_load &&
+ sds.this_load = sgs.avg_load;
+ sds.this = group;
+ sds.this_nr_running = sgs.sum_nr_running;
+ sds.this_load_per_task = sgs.sum_weighted_load;
+ } else if (sgs.avg_load > sds.max_load &&
(sgs.sum_nr_running > sgs.group_capacity ||
sgs.group_imb)) {
- max_load = sgs.avg_load;
- busiest = group;
- busiest_nr_running = sgs.sum_nr_running;
- busiest_load_per_task = sgs.sum_weighted_load;
- group_imb = sgs.group_imb;
+ sds.max_load = sgs.avg_load;
+ sds.busiest = group;
+ sds.busiest_nr_running = sgs.sum_nr_running;
+ sds.busiest_load_per_task = sgs.sum_weighted_load;
+ sds.group_imb = sgs.group_imb;
}
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
@@ -3409,15 +3433,16 @@ 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 >= sgs.group_capacity ||
- !this_nr_running))
- power_savings_balance = 0;
+ if (local_group &&
+ (sds.this_nr_running >= sgs.group_capacity ||
+ !sds.this_nr_running))
+ sds.power_savings_balance = 0;
/*
* If a group is already running at full capacity or idle,
* don't include that group in power savings calculations
*/
- if (!power_savings_balance ||
+ if (!sds.power_savings_balance ||
sgs.sum_nr_running >= sgs.group_capacity ||
!sgs.sum_nr_running)
goto group_next;
@@ -3427,12 +3452,13 @@ 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 ((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 = sgs.sum_nr_running;
- min_load_per_task = sgs.sum_weighted_load /
+ if ((sgs.sum_nr_running < sds.min_nr_running) ||
+ (sgs.sum_nr_running == sds.min_nr_running &&
+ group_first_cpu(group) >
+ group_first_cpu(sds.group_min))) {
+ sds.group_min = group;
+ sds.min_nr_running = sgs.sum_nr_running;
+ sds.min_load_per_task = sgs.sum_weighted_load /
sgs.sum_nr_running;
}
@@ -3444,29 +3470,32 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
if (sgs.sum_nr_running > sgs.group_capacity - 1)
goto group_next;
- 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 = sgs.sum_nr_running;
+ if (sgs.sum_nr_running > sds.leader_nr_running ||
+ (sgs.sum_nr_running == sds.leader_nr_running &&
+ group_first_cpu(group) <
+ group_first_cpu(sds.group_leader))) {
+ sds.group_leader = group;
+ sds.leader_nr_running = sgs.sum_nr_running;
}
group_next:
#endif
group = group->next;
} while (group != sd->groups);
- if (!busiest || this_load >= max_load || busiest_nr_running == 0)
+ if (!sds.busiest || sds.this_load >= sds.max_load
+ || sds.busiest_nr_running == 0)
goto out_balanced;
- avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
+ sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
- if (this_load >= avg_load ||
- 100*max_load <= sd->imbalance_pct*this_load)
+ if (sds.this_load >= sds.avg_load ||
+ 100*sds.max_load <= sd->imbalance_pct * sds.this_load)
goto out_balanced;
- busiest_load_per_task /= busiest_nr_running;
- if (group_imb)
- busiest_load_per_task = min(busiest_load_per_task, avg_load);
+ sds.busiest_load_per_task /= sds.busiest_nr_running;
+ if (sds.group_imb)
+ sds.busiest_load_per_task =
+ min(sds.busiest_load_per_task, sds.avg_load);
/*
* We're trying to get all the cpus to the average_load, so we don't
@@ -3479,7 +3508,7 @@ group_next:
* by pulling tasks to us. Be careful of negative numbers as they'll
* appear as very large values with unsigned longs.
*/
- if (max_load <= busiest_load_per_task)
+ if (sds.max_load <= sds.busiest_load_per_task)
goto out_balanced;
/*
@@ -3487,17 +3516,18 @@ group_next:
* max load less than avg load(as we skip the groups at or below
* its cpu_power, while calculating max_load..)
*/
- if (max_load < avg_load) {
+ if (sds.max_load < sds.avg_load) {
*imbalance = 0;
goto small_imbalance;
}
/* Don't want to pull so many tasks that a group would go idle */
- max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
+ max_pull = min(sds.max_load - sds.avg_load,
+ sds.max_load - sds.busiest_load_per_task);
/* How much load to actually move to equalise the imbalance */
- *imbalance = min(max_pull * busiest->__cpu_power,
- (avg_load - this_load) * this->__cpu_power)
+ *imbalance = min(max_pull * sds.busiest->__cpu_power,
+ (sds.avg_load - sds.this_load) * sds.this->__cpu_power)
/ SCHED_LOAD_SCALE;
/*
@@ -3506,24 +3536,27 @@ group_next:
* a think about bumping its value to force at least one task to be
* moved
*/
- if (*imbalance < busiest_load_per_task) {
+ if (*imbalance < sds.busiest_load_per_task) {
unsigned long tmp, pwr_now, pwr_move;
unsigned int imbn;
small_imbalance:
pwr_move = pwr_now = 0;
imbn = 2;
- if (this_nr_running) {
- this_load_per_task /= this_nr_running;
- if (busiest_load_per_task > this_load_per_task)
+ if (sds.this_nr_running) {
+ sds.this_load_per_task /= sds.this_nr_running;
+ if (sds.busiest_load_per_task >
+ sds.this_load_per_task)
imbn = 1;
} else
- this_load_per_task = cpu_avg_load_per_task(this_cpu);
-
- if (max_load - this_load + busiest_load_per_task >=
- busiest_load_per_task * imbn) {
- *imbalance = busiest_load_per_task;
- return busiest;
+ sds.this_load_per_task =
+ cpu_avg_load_per_task(this_cpu);
+
+ if (sds.max_load - sds.this_load +
+ sds.busiest_load_per_task >=
+ sds.busiest_load_per_task * imbn) {
+ *imbalance = sds.busiest_load_per_task;
+ return sds.busiest;
}
/*
@@ -3532,52 +3565,54 @@ small_imbalance:
* moving them.
*/
- pwr_now += busiest->__cpu_power *
- min(busiest_load_per_task, max_load);
- pwr_now += this->__cpu_power *
- min(this_load_per_task, this_load);
+ pwr_now += sds.busiest->__cpu_power *
+ 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;
/* Amount of load we'd subtract */
- tmp = sg_div_cpu_power(busiest,
- busiest_load_per_task * SCHED_LOAD_SCALE);
- if (max_load > tmp)
- pwr_move += busiest->__cpu_power *
- min(busiest_load_per_task, max_load - tmp);
+ tmp = sg_div_cpu_power(sds.busiest,
+ sds.busiest_load_per_task * SCHED_LOAD_SCALE);
+ if (sds.max_load > tmp)
+ pwr_move += sds.busiest->__cpu_power *
+ min(sds.busiest_load_per_task,
+ sds.max_load - tmp);
/* Amount of load we'd add */
- if (max_load * busiest->__cpu_power <
- busiest_load_per_task * SCHED_LOAD_SCALE)
- tmp = sg_div_cpu_power(this,
- max_load * 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);
else
- tmp = sg_div_cpu_power(this,
- busiest_load_per_task * SCHED_LOAD_SCALE);
- pwr_move += this->__cpu_power *
- min(this_load_per_task, this_load + tmp);
+ tmp = sg_div_cpu_power(sds.this,
+ sds.busiest_load_per_task * SCHED_LOAD_SCALE);
+ pwr_move += sds.this->__cpu_power *
+ min(sds.this_load_per_task,
+ sds.this_load + tmp);
pwr_move /= SCHED_LOAD_SCALE;
/* Move if we gain throughput */
if (pwr_move > pwr_now)
- *imbalance = busiest_load_per_task;
+ *imbalance = sds.busiest_load_per_task;
}
- return busiest;
+ return sds.busiest;
out_balanced:
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
goto ret;
- if (this != group_leader || group_leader == group_min)
+ if (sds.this != sds.group_leader || sds.group_leader == sds.group_min)
goto ret;
- *imbalance = min_load_per_task;
+ *imbalance = sds.min_load_per_task;
if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
- group_first_cpu(group_leader);
+ group_first_cpu(sds.group_leader);
}
- return group_min;
+ return sds.group_min;
#endif
ret:
--
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