From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754089AbYKMSqL (ORCPT ); Thu, 13 Nov 2008 13:46:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751840AbYKMSp4 (ORCPT ); Thu, 13 Nov 2008 13:45:56 -0500 Received: from one.firstfloor.org ([213.235.205.2]:35583 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751618AbYKMSpz (ORCPT ); Thu, 13 Nov 2008 13:45:55 -0500 Date: Thu, 13 Nov 2008 19:55:15 +0100 From: Andi Kleen To: Steven Rostedt Cc: Andi Kleen , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Ingo Molnar , Linux Kernel Subject: Re: [PATCH 1/2] tracing/function-return-tracer: Make the function return tracer lockless Message-ID: <20081113185515.GA3810@one.firstfloor.org> References: <491B4F0A.3080901@gmail.com> <87od0jd6ds.fsf@basil.nowhere.org> <20081113171220.GX3810@one.firstfloor.org> <20081113173451.GY3810@one.firstfloor.org> <20081113182937.GZ3810@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Now tell me again how local_* is more efficient than barrier? Look at the generated assembler, not the source. The M386 check is two instructions with the i386 stuff just moved away somewhere out of line that is about never taken. The rest is short and straight forward in asm too. And a lot of kernels are not compiled with 386 support anyways. -Andi -- ak@linux.intel.com