[tip:sched/core] sched/fair: Remove duplicate load_per_task computations

From: tip-bot for Peter Zijlstra
Date: Mon Sep 02 2013 - 03:41:24 EST


Commit-ID: 38d0f7708543bcfa03d5ee55e8346f801b4a59c9
Gitweb: http://git.kernel.org/tip/38d0f7708543bcfa03d5ee55e8346f801b4a59c9
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Thu, 15 Aug 2013 19:47:56 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 2 Sep 2013 08:27:36 +0200

sched/fair: Remove duplicate load_per_task computations

Since we already compute (but don't store) the sgs load_per_task value
in update_sg_lb_stats() we might as well store it and not re-compute
it later on.

Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-ym1vmljiwbzgdnnrwp9azftq@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 4c6a8a5..5795219 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4476,7 +4476,6 @@ static inline void update_sg_lb_stats(struct lb_env *env,
{
unsigned long nr_running, max_nr_running, min_nr_running;
unsigned long load, max_cpu_load, min_cpu_load;
- unsigned long avg_load_per_task = 0;
int i;

/* Tally up the load of all CPUs in the group */
@@ -4531,9 +4530,9 @@ static inline void update_sg_lb_stats(struct lb_env *env,
* the hierarchy?
*/
if (sgs->sum_nr_running)
- avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
+ sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;

- if ((max_cpu_load - min_cpu_load) >= avg_load_per_task &&
+ if ((max_cpu_load - min_cpu_load) >= sgs->load_per_task &&
(max_nr_running - min_nr_running) > 1)
sgs->group_imb = 1;

@@ -4776,15 +4775,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
struct sg_lb_stats *local, *busiest;

local = &sds->local_stat;
- if (local->sum_nr_running) {
- local->load_per_task =
- local->sum_weighted_load / local->sum_nr_running;
- }
-
busiest = &sds->busiest_stat;
- /* busiest must have some tasks */
- busiest->load_per_task =
- busiest->sum_weighted_load / busiest->sum_nr_running;

if (busiest->group_imb) {
busiest->load_per_task =
--
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