From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754617AbXLKPyx (ORCPT ); Tue, 11 Dec 2007 10:54:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751631AbXLKPyp (ORCPT ); Tue, 11 Dec 2007 10:54:45 -0500 Received: from smtpq2.tilbu1.nb.home.nl ([213.51.146.201]:36227 "EHLO smtpq2.tilbu1.nb.home.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751007AbXLKPyo (ORCPT ); Tue, 11 Dec 2007 10:54:44 -0500 Message-ID: <475EB263.2050405@keyaccess.nl> Date: Tue, 11 Dec 2007 16:53:07 +0100 From: Rene Herman User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Paul Rolland CC: David Newall , "H. Peter Anvin" , Krzysztof Halasa , Pavel Machek , Andi Kleen , Alan Cox , "David P. Reed" , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , rol@witbe.net Subject: Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops References: <475879CD.9080006@reed.com> <20071207160439.71b7f46a@the-village.bc.nu> <20071209125458.GB4381@ucw.cz> <20071209165908.GA15910@one.firstfloor.org> <20071209212513.GC24284@elf.ucw.cz> <475CBDD7.5050602@keyaccess.nl> <475DE37F.20706@davidnewall.com> <475DE6F4.80702@zytor.com> <475DEB23.1000304@davidnewall.com> <20071211084059.3d03e11d@tux.DEF.witbe.net> <475E5D4B.8020101@keyaccess.nl> <475E7DC2.4060509@davidnewall.com> <475E8D91.20201@keyaccess.nl> <20071211143224.15900995@tux.DEF.witbe.net> <475E9B9B.2050709@keyaccess.nl> <475EACB8.7080608@keyaccess.nl> <20071211163706.2dc82275@tux.DEF.witbe.net> In-Reply-To: <20071211163706.2dc82275@tux.DEF.witbe.net> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -1.0 (-) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11-12-07 16:37, Paul Rolland wrote: Great, thanks for the quick replies. That last one below especially is quite a bit more than 1. As said before, most hardware isn't in fact going to need anything but I suppose udelay(2) might be the "safer" replacement for the outb then... > On Tue, 11 Dec 2007 16:28:56 +0100 > Rene Herman wrote: > >> On 11-12-07 15:15, Rene Herman wrote: >> >>> On 11-12-07 14:32, Paul Rolland wrote: >>> >> This might be a bit more constant, I suppose. This serialises with cpuid. >> Don't see a difference locally, but perhaps you do. > Well, yes, at least on the PIII and the Opteron... Core2 is still changing > a lot... > >> On a Duron 1300 with an actual ISA bus, "out" is between 1300 and 1600 for >> me and "in" between 1200 and 1500 with a few flukes above that which will I >> suppose be caused by the bus (ISA _or_ PCI) being momentarily busy or some >> such... > The results : > > Core 2Duo 1.73 GHz : > [root@tux tmp]# ./in2 > out: 2777 > in : 2519 > [root@tux tmp]# ./in2 > out: 2440 > in : 2391 > [root@tux tmp]# ./in2 > out: 2460 > in : 2388 Okayish I guess, especially when subsequent runs stay near those values. 2500/1730 = 1.45 us > Pentium III : > [root@www-dev /tmp]# ./in2 > out: 746 > in : 747 > [root@www-dev /tmp]# ./in2 > out: 746 > in : 747 > [root@www-dev /tmp]# ./in2 > out: 746 > in : 745 746/600 ~= 1.24 us > AMD Opteron 150 : > -bash-3.1# ./in2 > out: 4846 > in : 4845 > -bash-3.1# ./in2 > out: 4846 > in : 4846 > -bash-3.1# ./in2 > out: 4846 > in : 4845 4846 / 2400 = 2.02 us Rene.