From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758182AbZEVUgp (ORCPT ); Fri, 22 May 2009 16:36:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756952AbZEVUgi (ORCPT ); Fri, 22 May 2009 16:36:38 -0400 Received: from one.firstfloor.org ([213.235.205.2]:50940 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756879AbZEVUgh (ORCPT ); Fri, 22 May 2009 16:36:37 -0400 Date: Fri, 22 May 2009 22:42:46 +0200 From: Andi Kleen To: "Michael S. Zick" Cc: Samuel Thibault , Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [BUG FIX] Make x86_32 uni-processor Atomic ops, Atomic Message-ID: <20090522204246.GH846@one.firstfloor.org> References: <200905221139.26941.lkml@morethan.org> <200905221453.41895.lkml@morethan.org> <20090522200536.GZ10166@const.famille.thibault.fr> <200905221532.43775.lkml@morethan.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200905221532.43775.lkml@morethan.org> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > 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. -Andi -- ak@linux.intel.com -- Speaking for myself only.