From 4bf0b77158d581c952af237aec79d0604b78fe27 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 25 Jan 2008 21:08:21 +0100
Subject: [PATCH] sched: remove do_div() from __sched_slice()
Yanmin Zhang noticed a nice optimization:
p = l * nr / nl, nl = l/g -> p = g * nr
which eliminates a do_div() from __sched_period().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched_fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 2208692dc4a00..10aa6e1ae3dde 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -248,8 +248,8 @@ static u64 __sched_period(unsigned long nr_running)
unsigned long nr_latency = sched_nr_latency;
if (unlikely(nr_running > nr_latency)) {
+ period = sysctl_sched_min_granularity;
period *= nr_running;
- do_div(period, nr_latency);
}
return period;
--
2.30.2