From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262491AbTIPUzq (ORCPT ); Tue, 16 Sep 2003 16:55:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262493AbTIPUzq (ORCPT ); Tue, 16 Sep 2003 16:55:46 -0400 Received: from havoc.gtf.org ([63.247.75.124]:60098 "EHLO havoc.gtf.org") by vger.kernel.org with ESMTP id S262491AbTIPUzp (ORCPT ); Tue, 16 Sep 2003 16:55:45 -0400 Date: Tue, 16 Sep 2003 16:55:45 -0400 From: Jeff Garzik To: Pavel Machek Cc: Manfred Spraul , linux-kernel@vger.kernel.org Subject: Re: [PATCH] add likely around access_ok for uaccess Message-ID: <20030916205545.GA14153@gtf.org> References: <3F644E36.5010402@colorfullife.com> <20030916194929.GF602@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030916194929.GF602@elf.ucw.cz> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 16, 2003 at 09:49:29PM +0200, Pavel Machek wrote: > Hi! > > > while trying to figure out why sysv msg is around 30% slower than pipes > > for data transfers I noticed that gcc's autodetection (3.2.2) guesses > > the "if(access_ok())" tests in uaccess.h wrong and puts the error memset > > into the direct path and the copy out of line. > > > > The attached patch adds likely to the tests - any objections? What about > > the archs except i386? > > How much speedup did you gain? How much can it hurt? Jeff