From 1091985b482fdd577a5c511059b9d7b4467bd15d Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 15 Oct 2007 17:00:04 +0200
Subject: [PATCH] sched: speed up update_load_add/_sub()
speed up update_load_add/_sub() by not delaying the division - this
reduces CPU pipeline dependencies.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/sched.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 3209e2cc2c2e..992a1fae72a7 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -697,16 +697,17 @@ calc_delta_fair(unsigned long delta_exec, struct load_weight *lw)
return calc_delta_mine(delta_exec, NICE_0_LOAD, lw);
}
-static void update_load_add(struct load_weight *lw, unsigned long inc)
+static inline void update_load_add(struct load_weight *lw, unsigned long inc)
{
lw->weight += inc;
- lw->inv_weight = 0;
+ lw->inv_weight = WMULT_CONST / lw->weight;
}
-static void update_load_sub(struct load_weight *lw, unsigned long dec)
+static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
{
lw->weight -= dec;
- lw->inv_weight = 0;
+ if (likely(lw->weight))
+ lw->inv_weight = WMULT_CONST / lw->weight;
}
/*