* [PATCH] sched: fix: remove double calculation in fix_small_imbalance
@ 2014-03-11 16:26 Vincent Guittot
2014-03-12 9:00 ` Peter Zijlstra
2014-03-12 10:10 ` [tip:sched/core] sched: Remove double calculation in fix_small_imbalance() tip-bot for Vincent Guittot
0 siblings, 2 replies; 4+ messages in thread
From: Vincent Guittot @ 2014-03-11 16:26 UTC (permalink / raw)
To: peterz, mingo, linux-kernel; +Cc: Vincent Guittot
The tmp value has been already calculated in:
scaled_busy_load_per_task =
(busiest->load_per_task * SCHED_POWER_SCALE) /
busiest->group_power;
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/fair.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f1eedae..b301918 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6061,12 +6061,10 @@ void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
pwr_now /= SCHED_POWER_SCALE;
/* Amount of load we'd subtract */
- tmp = (busiest->load_per_task * SCHED_POWER_SCALE) /
- busiest->group_power;
- if (busiest->avg_load > tmp) {
+ if (busiest->avg_load > scaled_busy_load_per_task) {
pwr_move += busiest->group_power *
min(busiest->load_per_task,
- busiest->avg_load - tmp);
+ busiest->avg_load - scaled_busy_load_per_task);
}
/* Amount of load we'd add */
--
1.9.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix: remove double calculation in fix_small_imbalance
2014-03-11 16:26 [PATCH] sched: fix: remove double calculation in fix_small_imbalance Vincent Guittot
@ 2014-03-12 9:00 ` Peter Zijlstra
2014-03-12 12:56 ` Vincent Guittot
2014-03-12 10:10 ` [tip:sched/core] sched: Remove double calculation in fix_small_imbalance() tip-bot for Vincent Guittot
1 sibling, 1 reply; 4+ messages in thread
From: Peter Zijlstra @ 2014-03-12 9:00 UTC (permalink / raw)
To: Vincent Guittot; +Cc: mingo, linux-kernel
On Tue, Mar 11, 2014 at 05:26:06PM +0100, Vincent Guittot wrote:
> The tmp value has been already calculated in:
> scaled_busy_load_per_task =
> (busiest->load_per_task * SCHED_POWER_SCALE) /
> busiest->group_power;
You created a little confusion in my brain by saying it was a fix; while
in fact it is an optimization removing duplicate computation.
I've changed the Subject to read:
sched: Remove double calculation in fix_small_imbalance
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip:sched/core] sched: Remove double calculation in fix_small_imbalance()
2014-03-11 16:26 [PATCH] sched: fix: remove double calculation in fix_small_imbalance Vincent Guittot
2014-03-12 9:00 ` Peter Zijlstra
@ 2014-03-12 10:10 ` tip-bot for Vincent Guittot
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Vincent Guittot @ 2014-03-12 10:10 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, peterz, vincent.guittot, tglx
Commit-ID: a2cd42601b474b957e1a5fe3692bcf7f9363bd51
Gitweb: http://git.kernel.org/tip/a2cd42601b474b957e1a5fe3692bcf7f9363bd51
Author: Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Tue, 11 Mar 2014 17:26:06 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 12 Mar 2014 10:49:00 +0100
sched: Remove double calculation in fix_small_imbalance()
The tmp value has been already calculated in:
scaled_busy_load_per_task =
(busiest->load_per_task * SCHED_POWER_SCALE) /
busiest->group_power;
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1394555166-22894-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/fair.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f1eedae..b301918 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6061,12 +6061,10 @@ void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
pwr_now /= SCHED_POWER_SCALE;
/* Amount of load we'd subtract */
- tmp = (busiest->load_per_task * SCHED_POWER_SCALE) /
- busiest->group_power;
- if (busiest->avg_load > tmp) {
+ if (busiest->avg_load > scaled_busy_load_per_task) {
pwr_move += busiest->group_power *
min(busiest->load_per_task,
- busiest->avg_load - tmp);
+ busiest->avg_load - scaled_busy_load_per_task);
}
/* Amount of load we'd add */
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix: remove double calculation in fix_small_imbalance
2014-03-12 9:00 ` Peter Zijlstra
@ 2014-03-12 12:56 ` Vincent Guittot
0 siblings, 0 replies; 4+ messages in thread
From: Vincent Guittot @ 2014-03-12 12:56 UTC (permalink / raw)
To: Peter Zijlstra; +Cc: Ingo Molnar, linux-kernel
On 12 March 2014 10:00, Peter Zijlstra <peterz@infradead.org> wrote:
> On Tue, Mar 11, 2014 at 05:26:06PM +0100, Vincent Guittot wrote:
>> The tmp value has been already calculated in:
>> scaled_busy_load_per_task =
>> (busiest->load_per_task * SCHED_POWER_SCALE) /
>> busiest->group_power;
>
> You created a little confusion in my brain by saying it was a fix; while
> in fact it is an optimization removing duplicate computation.
sorry for the confusion.
>
> I've changed the Subject to read:
>
> sched: Remove double calculation in fix_small_imbalance
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-03-12 12:56 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2014-03-11 16:26 [PATCH] sched: fix: remove double calculation in fix_small_imbalance Vincent Guittot
2014-03-12 9:00 ` Peter Zijlstra
2014-03-12 12:56 ` Vincent Guittot
2014-03-12 10:10 ` [tip:sched/core] sched: Remove double calculation in fix_small_imbalance() tip-bot for Vincent Guittot
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