From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Mike Galbraith <efault@gmx.de>,
Paul Turner <pjt@google.com>, Alex Shi <alex.shi@intel.com>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
Joonsoo Kim <js1304@gmail.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: [PATCH v3 1/3] sched: remove one division operation in find_buiest_queue()
Date: Tue, 6 Aug 2013 17:36:41 +0900 [thread overview]
Message-ID: <1375778203-31343-2-git-send-email-iamjoonsoo.kim@lge.com> (raw)
In-Reply-To: <1375778203-31343-1-git-send-email-iamjoonsoo.kim@lge.com>
Remove one division operation in find_buiest_queue().
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9565645..52898dc 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4968,7 +4968,7 @@ static struct rq *find_busiest_queue(struct lb_env *env,
struct sched_group *group)
{
struct rq *busiest = NULL, *rq;
- unsigned long max_load = 0;
+ unsigned long busiest_load = 0, busiest_power = SCHED_POWER_SCALE;
int i;
for_each_cpu(i, sched_group_cpus(group)) {
@@ -4999,10 +4999,9 @@ static struct rq *find_busiest_queue(struct lb_env *env,
* the load can be moved away from the cpu that is potentially
* running at a lower capacity.
*/
- wl = (wl * SCHED_POWER_SCALE) / power;
-
- if (wl > max_load) {
- max_load = wl;
+ if (wl * busiest_power > busiest_load * power) {
+ busiest_load = wl;
+ busiest_power = power;
busiest = rq;
}
}
--
1.7.9.5
next prev parent reply other threads:[~2013-08-06 8:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 8:36 [PATCH v3 0/3] optimization, clean-up about fair.c Joonsoo Kim
2013-08-06 8:36 ` Joonsoo Kim [this message]
2013-09-02 7:40 ` [tip:sched/core] sched: Remove one division operation in find_busiest_queue() tip-bot for Joonsoo Kim
2013-08-06 8:36 ` [PATCH v3 2/3] sched: factor out code to should_we_balance() Joonsoo Kim
2013-08-15 11:19 ` Peter Zijlstra
2013-08-16 16:52 ` JoonSoo Kim
2013-08-15 12:34 ` Peter Zijlstra
2013-08-16 16:57 ` JoonSoo Kim
2013-09-02 7:40 ` [tip:sched/core] sched: Factor " tip-bot for Joonsoo Kim
2013-08-06 8:36 ` [PATCH v3 3/3] sched: clean-up struct sd_lb_stat Joonsoo Kim
2013-08-15 11:09 ` Peter Zijlstra
2013-08-15 11:14 ` Peter Zijlstra
2013-08-16 17:07 ` JoonSoo Kim
2013-08-15 18:05 ` Peter Zijlstra
2013-08-16 17:09 ` JoonSoo Kim
2013-09-02 7:40 ` [tip:sched/core] sched: Clean-up " tip-bot for Joonsoo Kim
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