From owner-svn-src-all@FreeBSD.ORG  Wed Oct 31 17:12:13 2012
Return-Path: <owner-svn-src-all@FreeBSD.ORG>
Delivered-To: svn-src-all@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
 by hub.freebsd.org (Postfix) with ESMTP id 940194B4;
 Wed, 31 Oct 2012 17:12:13 +0000 (UTC)
 (envelope-from jimharris@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c])
 by mx1.freebsd.org (Postfix) with ESMTP id 7B89D8FC14;
 Wed, 31 Oct 2012 17:12:13 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
 by svn.freebsd.org (8.14.4/8.14.4) with ESMTP id q9VHCD0g090320;
 Wed, 31 Oct 2012 17:12:13 GMT
 (envelope-from jimharris@svn.freebsd.org)
Received: (from jimharris@localhost)
 by svn.freebsd.org (8.14.4/8.14.4/Submit) id q9VHCDZI090317;
 Wed, 31 Oct 2012 17:12:13 GMT
 (envelope-from jimharris@svn.freebsd.org)
Message-Id: <201210311712.q9VHCDZI090317@svn.freebsd.org>
From: Jim Harris <jimharris@FreeBSD.org>
Date: Wed, 31 Oct 2012 17:12:13 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r242401 - head/sys/kern
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
 user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 31 Oct 2012 17:12:13 -0000

Author: jimharris
Date: Wed Oct 31 17:12:12 2012
New Revision: 242401
URL: http://svn.freebsd.org/changeset/base/242401

Log:
  Pad and align the callout_cpu mtx to its own cacheline to reduce false
  sharing especially on the default CPU 0 callout_cpu structure.
  
  This will be followed up by attilio@ with a conversion to the new struct
  mtx_padalign but doing this manual conversion first gives an easy MFC
  candidate since mtx_padalign is a more extensive system change.
  
  Sponsored by:	Intel
  Reviewed by:	jeff, attilio
  MFC after:	1 week

Modified:
  head/sys/kern/kern_timeout.c

Modified: head/sys/kern/kern_timeout.c
==============================================================================
--- head/sys/kern/kern_timeout.c	Wed Oct 31 17:01:56 2012	(r242400)
+++ head/sys/kern/kern_timeout.c	Wed Oct 31 17:12:12 2012	(r242401)
@@ -119,8 +119,8 @@ struct cc_mig_ent {
  *	when the callout should be served.
  */
 struct callout_cpu {
-	struct cc_mig_ent	cc_migrating_entity;
 	struct mtx		cc_lock;
+	struct cc_mig_ent	cc_migrating_entity __aligned(CACHE_LINE_SIZE);
 	struct callout		*cc_callout;
 	struct callout_tailq	*cc_callwheel;
 	struct callout_list	cc_callfree;