Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757499AbZGCMoT (ORCPT ); Fri, 3 Jul 2009 08:44:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753268AbZGCMoJ (ORCPT ); Fri, 3 Jul 2009 08:44:09 -0400 Received: from hera.kernel.org ([140.211.167.34]:59822 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753087AbZGCMoH (ORCPT ); Fri, 3 Jul 2009 08:44:07 -0400 Date: Fri, 3 Jul 2009 12:42:34 GMT From: tip-bot for Eric Dumazet 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, eric.dumazet@gmail.com, a.p.zijlstra@chello.nl, torvalds@linux-foundation.org, efault@gmx.de, arnd@arndb.de, dhowells@redhat.com, fweisbec@gmail.com, akpm@linux-foundation.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, acme@redhat.com, linux-kernel@vger.kernel.org, eric.dumazet@gmail.com, torvalds@linux-foundation.org, a.p.zijlstra@chello.nl, efault@gmx.de, arnd@arndb.de, fweisbec@gmail.com, dhowells@redhat.com, akpm@linux-foundation.org, tglx@linutronix.de, mingo@elte.hu In-Reply-To: References: Subject: [tip:perfcounters/urgent] x86: atomic64: The atomic64_t data type should be 8 bytes aligned on 32-bit too Message-ID: Git-Commit-ID: bbf2a330d92c5afccfd17592ba9ccd50f41cf748 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 03 Jul 2009 12:42:36 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2018 Lines: 53 Commit-ID: bbf2a330d92c5afccfd17592ba9ccd50f41cf748 Gitweb: http://git.kernel.org/tip/bbf2a330d92c5afccfd17592ba9ccd50f41cf748 Author: Eric Dumazet AuthorDate: Fri, 3 Jul 2009 00:08:26 +0200 Committer: Ingo Molnar CommitDate: Fri, 3 Jul 2009 13:26:38 +0200 x86: atomic64: The atomic64_t data type should be 8 bytes aligned on 32-bit too Locked instructions on two cache lines at once are painful. If atomic64_t uses two cache lines, my test program is 10x slower. The chance for that is significant: 4/32 or 12.5%. Make sure an atomic64_t is 8 bytes aligned. Signed-off-by: Eric Dumazet Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: David Howells Cc: Andrew Morton Cc: Arnd Bergmann LKML-Reference: [ changed it to __aligned(8) as per Andrew's suggestion ] Signed-off-by: Ingo Molnar --- arch/x86/include/asm/atomic_32.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h index 2503d4e..ae0fbb5 100644 --- a/arch/x86/include/asm/atomic_32.h +++ b/arch/x86/include/asm/atomic_32.h @@ -250,7 +250,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u) /* An 64bit atomic type */ typedef struct { - unsigned long long counter; + unsigned long long __aligned(8) counter; } atomic64_t; #define ATOMIC64_INIT(val) { (val) } -- 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/