Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752174AbXLLVTV (ORCPT ); Wed, 12 Dec 2007 16:19:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751433AbXLLVTD (ORCPT ); Wed, 12 Dec 2007 16:19:03 -0500 Received: from terminus.zytor.com ([198.137.202.10]:47619 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752789AbXLLVTA (ORCPT ); Wed, 12 Dec 2007 16:19:00 -0500 Message-ID: <47604C6F.1090409@zytor.com> Date: Wed, 12 Dec 2007 13:02:39 -0800 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Rene Herman CC: =?ISO-8859-15?Q?Alejandro_Riveira_Fern=E1ndez?= , Linux Kernel , dpreed@reed.com, Alan Cox , pavel@ucw.cz, andi@firstfloor.org, rol@as2917.net, Krzysztof Halasa , david@davidnewall.com, john@stoffel.org, linux-os@analogic.com Subject: Re: [RFT] Port 0x80 I/O speed References: <475F1DC6.5090403@keyaccess.nl> <20071212004316.079e3a05@Varda> <475F227D.7050203@keyaccess.nl> <20071212010928.3c763ccd@Varda> <475F2846.1010402@keyaccess.nl> In-Reply-To: <475F2846.1010402@keyaccess.nl> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1340 Lines: 41 Rene Herman wrote: > On 12-12-07 01:09, Alejandro Riveira Fern?ndez wrote: > >>>> On my AMD 3800 X2 (2000MHz) ULi M1697 2.6.24-rc5 i get: >>>> >>>> cycles: out 1844674407370808, in 1844674407369087 >>>> >>>> It is not constant but variations are not significant afaics >>> Eh, oh, I guess you need to compile as a 32-bit binary... >> >> I tried without -O2 as Nigel Cunningham... >> >> cycles: out 1562, in 865 >> cycles: out 1562, in 866 >> cycles: out 1555, in 858 >> cycles: out 1562, in 866 >> >> With -m32 -O2 >> cycles: out 1566, in 876 >> cycles: out 1555, in 865 >> cycles: out 1594, in 931 >> cycles: out 1559, in 874 > > Great, thanks much for reporting. Sort of interesting in itself that > without -O2 you do still get correct results on 64-bit but for some > other time. > > You're the first one to go significantly below 1 us it seems. Make sure the CPU is actually running at full frequency. It probably would have been better to have used gettimeofday() around a sufficiently big loop, so that we would have gotten wall time rather than cycles. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/