Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933593AbZKXQ55 (ORCPT ); Tue, 24 Nov 2009 11:57:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933566AbZKXQ54 (ORCPT ); Tue, 24 Nov 2009 11:57:56 -0500 Received: from hera.kernel.org ([140.211.167.34]:60347 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933652AbZKXQ5v (ORCPT ); Tue, 24 Nov 2009 11:57:51 -0500 Date: Tue, 24 Nov 2009 16:57:05 GMT From: tip-bot for Tim Blechmann 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 Reply-To: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, acme@redhat.com, linux-kernel@vger.kernel.org, fweisbec@gmail.com, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, tim@klingt.org, mingo@elte.hu In-Reply-To: <4B0BBB93.3080307@klingt.org> References: <4B0BBB93.3080307@klingt.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched, x86: Optimize branch hint in __switch_to() Message-ID: Git-Commit-ID: a3a1de0c34de6f5f8332cd6151c46af7813c0fcb X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1869 Lines: 52 Commit-ID: a3a1de0c34de6f5f8332cd6151c46af7813c0fcb Gitweb: http://git.kernel.org/tip/a3a1de0c34de6f5f8332cd6151c46af7813c0fcb Author: Tim Blechmann AuthorDate: Tue, 24 Nov 2009 11:55:15 +0100 Committer: Ingo Molnar CommitDate: Tue, 24 Nov 2009 12:20:04 +0100 sched, x86: Optimize branch hint in __switch_to() Branch hint profiling on my nehalem machine showed 96% incorrect branch hints: 6548732 174664120 96 __switch_to process_64.c 406 6548745 174565593 96 __switch_to process_64.c 410 Signed-off-by: Tim Blechmann Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: <4B0BBB93.3080307@klingt.org> Signed-off-by: Ingo Molnar --- arch/x86/kernel/process_64.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index ad535b6..d9db104 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -406,11 +406,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) * This won't pick up thread selector changes, but I guess that is ok. */ savesegment(es, prev->es); - if (unlikely(next->es | prev->es)) + if (next->es | prev->es) loadsegment(es, next->es); - savesegment(ds, prev->ds); - if (unlikely(next->ds | prev->ds)) + if (next->ds | prev->ds) loadsegment(ds, next->ds); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/