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From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: <nickpiggin@yahoo.com.au>, "'Ingo Molnar'" <mingo@elte.hu>,
	"Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: <linux-kernel@vger.kernel.org>
Subject: [patch] sched: optimize activate_task for RT task - v2
Date: Tue, 14 Nov 2006 15:55:10 -0800	[thread overview]
Message-ID: <000401c70848$520252e0$d834030a@amr.corp.intel.com> (raw)

Perhaps the following is a better patch compare to earlier one.
The p->sleep_type are only for SCHED_NORMAL as well, so we can
bypass them altogether in one shot.




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>

--- ./kernel/sched.c.orig	2006-11-14 13:29:37.000000000 -0800
+++ ./kernel/sched.c	2006-11-14 14:05:39.000000000 -0800
@@ -938,6 +938,9 @@ static void activate_task(struct task_st
 {
 	unsigned long long now;
 
+	if (rt_task(p))
+		goto out;
+
 	now = sched_clock();
 #ifdef CONFIG_SMP
 	if (!local) {
@@ -947,9 +950,7 @@ static void activate_task(struct task_st
 			+ rq->timestamp_last_tick;
 	}
 #endif
-
-	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
@@ -974,7 +975,7 @@ static void activate_task(struct task_st
 		}
 	}
 	p->timestamp = now;
-
+out:
 	__activate_task(p, rq);
 }
 

             reply	other threads:[~2006-11-14 23:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-14 23:55 Chen, Kenneth W [this message]
2006-11-15  7:00 ` [patch] sched: optimize activate_task for RT task - v2 Mike Galbraith
2006-11-15  8:24   ` Mike Galbraith

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