From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933836AbXHIBbF (ORCPT ); Wed, 8 Aug 2007 21:31:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753713AbXHIBay (ORCPT ); Wed, 8 Aug 2007 21:30:54 -0400 Received: from dsl081-033-126.lax1.dsl.speakeasy.net ([64.81.33.126]:43962 "EHLO bifrost.lang.hm" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754632AbXHIBax (ORCPT ); Wed, 8 Aug 2007 21:30:53 -0400 Date: Wed, 8 Aug 2007 18:26:24 -0700 (PDT) From: david@lang.hm X-X-Sender: dlang@asgard.lang.hm To: Greg Trounson cc: Ingo Molnar , Linux Kernel Mailing List Subject: Re: [PATCH 00/23] per device dirty throttling -v8 In-Reply-To: <46BA6667.1070205@maths.otago.ac.nz> Message-ID: References: <20070804103347.GA1956@elte.hu> <20070804163733.GA31001@elte.hu> <46B4C0A8.1000902@garzik.org> <20070804191205.GA24723@lazybastard.org> <20070804192130.GA25346@elte.hu> <20070804211156.5f600d80@the-village.bc.nu> <20070804202830.GA4538@elte.hu> <20070804224834.5187f9b7@the-village.bc.nu> <20070805071320.GC515@elte.hu> <46BA6667.1070205@maths.otago.ac.nz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Aug 2007, Greg Trounson wrote: >> Measurements show that noatime helps 20-30% on regular desktop workloads, >> easily 50% for kernel builds and much more than that (in excess of 100%) >> for file-read-intense workloads. We cannot just walk past such a _huge_ >> performance impact so easily without even reacting to the performance >> arguments, and i'm happy Ubuntu picked up noatime,nodiratime and is >> whipping up the floor with Fedora on the desktop. >> > > Sorry I'm just not seeing those gains here. With my filesystems mounted with > atime defaults the Quake sources build in 1m28.856s. A test with ls -ltu > verifies that atime is working as expected. When I remount my filesystems > with: > mount [fs] -o remount,noatime,nodiratime > I get a compile time of 1m23.368s, a mere 6% improvement. > > This is on a dual-core Athlon 4200+ box running 2.6.21, so I would have > thought this to be close to a best-case file I/O test. what sort of disks does this box have? and what filesystem? slower disks/filesystems can result in this showing a larger difference. however 6% is a fairly significant gain. David Lang