From 62ab616d54371a65f595c199aad1e1755b837d25 Mon Sep 17 00:00:00 2001
From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Date: Sun, 10 Dec 2006 02:20:36 -0800
Subject: [PATCH] [PATCH] sched: optimize activate_task for RT task
RT task does not participate in interactiveness priority and thus shouldn't
be bothered with timestamp and p->sleep_type manipulation when task is
being put on run queue. Bypass all of the them with a single if (rt_task)
test.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
kernel/sched.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 66e44b5b53d2..48e35c916326 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -940,6 +940,9 @@ static void activate_task(struct task_struct *p, struct rq *rq, int local)
{
unsigned long long now;
+ if (rt_task(p))
+ goto out;
+
now = sched_clock();
#ifdef CONFIG_SMP
if (!local) {
@@ -961,8 +964,7 @@ static void activate_task(struct task_struct *p, struct rq *rq, int local)
(now - p->timestamp) >> 20);
}
- if (!rt_task(p))
- p->prio = recalc_task_prio(p, now);
+ p->prio = recalc_task_prio(p, now);
/*
* This checks to make sure it's not an uninterruptible task
@@ -987,7 +989,7 @@ static void activate_task(struct task_struct *p, struct rq *rq, int local)
}
}
p->timestamp = now;
-
+out:
__activate_task(p, rq);
}
--
2.39.5