From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757363AbXJ0TEU (ORCPT ); Sat, 27 Oct 2007 15:04:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751639AbXJ0TEM (ORCPT ); Sat, 27 Oct 2007 15:04:12 -0400 Received: from main.gmane.org ([80.91.229.2]:33573 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751904AbXJ0TEM (ORCPT ); Sat, 27 Oct 2007 15:04:12 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Bill Davidsen Subject: Re: 2.6.24-rc1: First impressions Date: Sat, 27 Oct 2007 15:14:19 -0400 Message-ID: <47238E0B.2010601@tmr.com> References: <796505.25770.qm@web32612.mail.mud.yahoo.com> <20071026152221.GA26619@elte.hu> <20071026122155.45ce72e7.akpm@linux-foundation.org> <20071026193339.GA21799@elte.hu> <20071026124252.aba97af4.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org Cc: Ingo Molnar , spamtrap@knobisoft.de, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, wfg@mail.ustc.edu.cn, torvalds@linux-foundation.org, riel@redhat.com X-Gmane-NNTP-Posting-Host: pool-70-109-100-63.alb.east.verizon.net User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061105 SeaMonkey/1.0.6 In-Reply-To: <20071026124252.aba97af4.akpm@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Fri, 26 Oct 2007 21:33:40 +0200 > Ingo Molnar wrote: > >> * Andrew Morton wrote: >> >> so a final 'sync' should be added to the test too, and the time it takes >> factored into the bandwidth numbers? > > That's one way of doing it. Or just run the test for a "long" time. ie: > much longer than (total-memory / disk-bandwidth). Probably the latter > will give a more accurate result, but it can get boring. > Longer might be less inaccurate, but without flushing the last data you really don't get best accuracy, you just reduce the error. Clearly doing fdatasync() is best, since other i/o caused by sync() can skew the results. -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot