From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757496AbZEVU6F (ORCPT ); Fri, 22 May 2009 16:58:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757010AbZEVU5z (ORCPT ); Fri, 22 May 2009 16:57:55 -0400 Received: from mx-out.daemonmail.net ([216.104.160.38]:37490 "EHLO mx-out.daemonmail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756340AbZEVU5z (ORCPT ); Fri, 22 May 2009 16:57:55 -0400 From: "Michael S. Zick" Reply-To: lkml@morethan.org To: Andi Kleen Subject: Re: [BUG FIX] Make x86_32 uni-processor Atomic ops, Atomic Date: Fri, 22 May 2009 15:57:51 -0500 User-Agent: KMail/1.9.9 Cc: Samuel Thibault , linux-kernel@vger.kernel.org References: <200905221139.26941.lkml@morethan.org> <200905221532.43775.lkml@morethan.org> <20090522204246.GH846@one.firstfloor.org> In-Reply-To: <20090522204246.GH846@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200905221557.54195.lkml@morethan.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri May 22 2009, Andi Kleen wrote: > > If it: "Does not make a difference" then it "Should not make a difference" > > but it does, try it yourself. Its safe (if LOCK_PREFIX is in the proper > > places) - the machine will ignore the opcode if is recent enough to not > > need it - just trust the cpu's micro-code. > > It doesn't ignore it, in fact it's extremly slow on some older systems > where all atomic operations are very costly. > That is why LOCK is avoided as much as possible. > I'm only the messanger. Mike > -Andi