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From: tip-bot for Tim Blechmann <tim@klingt.org>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, acme@redhat.com, paulus@samba.org,
	hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl,
	efault@gmx.de, fweisbec@gmail.com, tglx@linutronix.de,
	tim@klingt.org, mingo@elte.hu
Subject: [tip:sched/core] sched: Optimize branch hint in pick_next_task_fair()
Date: Tue, 24 Nov 2009 16:56:36 GMT	[thread overview]
Message-ID: <tip-36ace27e3e60d44ea69ce394b2e45386ae98d9d9@git.kernel.org> (raw)
In-Reply-To: <4B0BBBB1.2050100@klingt.org>

Commit-ID:  36ace27e3e60d44ea69ce394b2e45386ae98d9d9
Gitweb:     http://git.kernel.org/tip/36ace27e3e60d44ea69ce394b2e45386ae98d9d9
Author:     Tim Blechmann <tim@klingt.org>
AuthorDate: Tue, 24 Nov 2009 11:55:45 +0100
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 24 Nov 2009 12:18:12 +0100

sched: Optimize branch hint in pick_next_task_fair()

Branch hint profiling on my nehalem machine showed 90%
incorrect branch hints:

  15728471 158903754  90 pick_next_task_fair
  sched_fair.c    1555

Signed-off-by: Tim Blechmann <tim@klingt.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B0BBBB1.2050100@klingt.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched_fair.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index f28a267..24086e7 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1704,7 +1704,7 @@ static struct task_struct *pick_next_task_fair(struct rq *rq)
 	struct cfs_rq *cfs_rq = &rq->cfs;
 	struct sched_entity *se;
 
-	if (unlikely(!cfs_rq->nr_running))
+	if (!cfs_rq->nr_running)
 		return NULL;
 
 	do {

  reply	other threads:[~2009-11-24 16:57 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1259059549.git.tim@klingt.org>
2009-11-24 10:55 ` [PATCH 1/5] process_64: remove branch hint Tim Blechmann
2009-11-24 16:57   ` [tip:sched/core] sched, x86: Optimize branch hint in __switch_to() tip-bot for Tim Blechmann
2009-11-24 17:28     ` Brian Gerst
2009-11-25  9:03       ` Tim Blechmann
2009-11-25 15:53         ` Brian Gerst
2009-11-25 16:16           ` index 780cd92..22db86a 100644 Brian Gerst
2009-11-25 16:17           ` [PATCH] x86, 64-bit: Set data segments to null after switching to 64-bit mode Brian Gerst
2009-11-26  9:56             ` [tip:x86/asm] " tip-bot for Brian Gerst
2009-11-29 11:44             ` [PATCH] " Tim Blechmann
2009-12-02 11:32     ` [PATCH] Revert "sched, x86: Optimize branch hint in __switch_to()" Tim Blechmann
2009-12-02 13:27       ` [tip:sched/core] " tip-bot for Tim Blechmann
2009-11-24 10:55 ` [PATCH 2/5] sched.c: change branch hint Tim Blechmann
2009-11-24 16:56   ` [tip:sched/core] sched: Optimize branch hint in context_switch() tip-bot for Tim Blechmann
2009-11-24 10:55 ` [PATCH 3/5] slab.c: remove branch hint Tim Blechmann
2009-11-24 11:20   ` Ingo Molnar
2009-11-24 11:28     ` Pekka Enberg
2009-11-24 11:42       ` Ingo Molnar
2009-11-25 10:41         ` Pekka Enberg
2009-11-24 11:45       ` Tim Blechmann
2009-11-29 11:36       ` Tim Blechmann
2009-11-30  9:05         ` Pekka Enberg
2009-11-30 16:09           ` Christoph Lameter
2009-11-30 17:44             ` Pekka Enberg
2009-11-30 17:50               ` Christoph Lameter
2009-11-30 17:59               ` [PATCH] branch profiling on my nehalem machine showed 99% incorrect branch hints: Tim Blechmann
2009-12-06  8:33                 ` Pekka Enberg
2009-11-24 10:55 ` [PATCH 4/5] sched_fair.c: remove branch hint Tim Blechmann
2009-11-24 16:56   ` tip-bot for Tim Blechmann [this message]
2009-11-24 10:55 ` [PATCH 5/5] workqueue.c: " Tim Blechmann

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