From: Michael Rubin Subject: Re: [PATCH 1/1] Allow ext4 to run without a journal. Date: Thu, 18 Dec 2008 10:13:13 -0800 Message-ID: <532480950812181013m76fef953s3b3fb517d708b383@mail.gmail.com> References: <1228953270.14314.15.camel@bobble.smo.corp.google.com> <20081218180004.GB6797@atrey.karlin.mff.cuni.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Frank Mayhar , linux-ext4@vger.kernel.org To: Jan Kara Return-path: Received: from smtp-out.google.com ([216.239.45.13]:33324 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752879AbYLRSNS (ORCPT ); Thu, 18 Dec 2008 13:13:18 -0500 Received: from zps75.corp.google.com (zps75.corp.google.com [172.25.146.75]) by smtp-out.google.com with ESMTP id mBIIDHLB015059 for ; Thu, 18 Dec 2008 10:13:17 -0800 Received: from el-out-1112.google.com (elfj27.prod.google.com [10.126.186.27]) by zps75.corp.google.com with ESMTP id mBIIDEsE000343 for ; Thu, 18 Dec 2008 10:13:14 -0800 Received: by el-out-1112.google.com with SMTP id j27so129203elf.15 for ; Thu, 18 Dec 2008 10:13:13 -0800 (PST) In-Reply-To: <20081218180004.GB6797@atrey.karlin.mff.cuni.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Dec 18, 2008 at 10:00 AM, Jan Kara wrote: > Interesting although I'm not that surprised because those tests seem > to do a lot of data changes (which are never journaled in fact) and tiny > amount of metadata changes. If you run some benchmark doing lots of > directory operations, I guess the numbers would be considerably > different. Actually we have some compile bench numbers (coming to this list soon) that also surprised us. The stages of compile bench that I believe are dominated by directory operations are also showing improvements without the journal. > Maybe trying dbench (I know it's kind of stupid ;) or > postmark will show the differences better. I admit also we see huge variance using dbench on subsequent runs. To the point where I don't know how much I trust it's numbers. Is this a tool that people on this list have a lot of faith in? mrubin