Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757072AbXKMQfV (ORCPT ); Tue, 13 Nov 2007 11:35:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754135AbXKMQfI (ORCPT ); Tue, 13 Nov 2007 11:35:08 -0500 Received: from victor.provo.novell.com ([137.65.250.26]:50559 "EHLO victor.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753085AbXKMQfH (ORCPT ); Tue, 13 Nov 2007 11:35:07 -0500 Message-ID: <4739D428.2010203@suse.de> Date: Wed, 14 Nov 2007 00:43:20 +0800 From: Coly Li Reply-To: coyli@suse.de Organization: SuSE Labs User-Agent: Thunderbird 2.0.0.6 (X11/20070801) MIME-Version: 1.0 CC: Alex Tomas , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ext4: dir inode reservation V3 References: <4739B0C0.3060907@suse.de> <4739B02A.2000209@gmail.com> <4739D067.5080907@suse.de> In-Reply-To: <4739D067.5080907@suse.de> X-Enigmail-Version: 0.95.5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2047 Lines: 52 Coly Li wrote: > Thanks for the feedback :-) > > Alex Tomas wrote: >> hmm. so you trade 265% degradation of creation for 40% improvement of >> unlink? >> > 265% degradation is only for creating 50000 empty directories. This is not a common case. > There are 13% improvement on create 15 files in each directories. Total time on creating these > directories and files are 25m6s VS. 24m86s, indeed, dir inode reservation is a little faster. Sorry a typo here, it's 25m6s VS. 24m7.86s. > > Maybe most of the people will not create dozens of empty directories in their applications, > therefore IMHO the 265% degradation is acceptable. > > If user really need to create so many empty directories, they also can mount the file system without > dir inode reservation to get better performance. > >> thanks, Alex >> >> Coly Li wrote: >>> normal ext4 ext4 with dir inode reservation >>> mount options: -o data=writeback -o >>> data=writeback,dir_ireserve=low >>> Create dirs: real 0m49.101s real 2m59.703s >>> Create files: real 24m17.962s real 21m8.161s >>> Unlink all: real 24m43.788s real 17m29.862s >>> Creating dirs with dir inode reservation is slower than normal ext4 as >>> predicted, because allocating >>> directory inodes in non-linear order will cause extra hard disk >>> seeking and block I/O. Creating >>> files with dir inode reservation is 13% faster than normal ext4. >>> Unlink all the directories and >>> files is 29.2% faster as expected. >>> When number of directories is increased, the performance improvement >>> will be more considerable. More >>> benchmark result will be posted here if necessary, because I need more >>> time to run more test cases. > -- Coly Li SuSE PRC Labs - 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/