From: Theodore Ts'o Subject: Re: A doubt on journal_async_commit option Date: Fri, 12 Dec 2014 09:54:43 -0500 Message-ID: <20141212145443.GB17783@thunk.org> References: <548A8534.1050606@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , linux-ext4@vger.kernel.org, Joseph Qi To: alex chen Return-path: Received: from imap.thunk.org ([74.207.234.97]:53125 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751585AbaLLOyv (ORCPT ); Fri, 12 Dec 2014 09:54:51 -0500 Content-Disposition: inline In-Reply-To: <548A8534.1050606@huawei.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Dec 12, 2014 at 02:03:32PM +0800, alex chen wrote: > This commit 0e3d2a6313(ext4: Fix async commit mode to be safe by using > a barrier) show that using journal_async_commit feature has a 50% > performance improvement. But I tested in SUSE Linux Enterprise Server > 11 SP3(linux kernel 3.0.93) and Red Hat Enterprise linux 6.4(linux > kernel 2.6.32), the result show this feature has no performance > improvement. > My test command: > mount /dev/sdb /mnt/sdb > ./fs_mark -d /mnt/sdb/ -s 10240 -n 1000 > umount > > mount /dev/sdb /mnt/sdb -o journal_async_commit > ./fs_mark -d /mnt/sdb/ -s 10240 -n 1000 > umount > > My test result: > FSUse% Count Size Files/sec App Overhead > 6 1000 10240 42.1 10671 > vs. > -o journal_async_commit > FSUse% Count Size Files/sec App Overhead > 6 1000 10240 63.9 10625 Um, the files per second went up from 42.1 to 63.9 --- that's a 50% improvement, yes? - Ted