From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: Yet another base64 patch Date: Wed, 13 Apr 2005 23:27:46 -0700 Message-ID: <425E0D62.9000401@zytor.com> References: <425DEF64.60108@zytor.com> <20050414022413.GB18655@64m.dyndns.org> <425E0174.4080404@zytor.com> <20050414024228.GC18655@64m.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: git@vger.kernel.org X-From: git-owner@vger.kernel.org Thu Apr 14 08:25:44 2005 Return-path: Received: from vger.kernel.org ([12.107.209.244]) by ciao.gmane.org with esmtp (Exim 4.43) id 1DLxmE-00066I-3G for gcvg-git@gmane.org; Thu, 14 Apr 2005 08:24:34 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261399AbVDNG1w (ORCPT ); Thu, 14 Apr 2005 02:27:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261439AbVDNG1w (ORCPT ); Thu, 14 Apr 2005 02:27:52 -0400 Received: from terminus.zytor.com ([209.128.68.124]:44516 "EHLO terminus.zytor.com") by vger.kernel.org with ESMTP id S261399AbVDNG1u (ORCPT ); Thu, 14 Apr 2005 02:27:50 -0400 Received: from [172.27.0.18] (c-67-169-23-106.hsd1.ca.comcast.net [67.169.23.106]) (authenticated bits=0) by terminus.zytor.com (8.13.1/8.13.1) with ESMTP id j3E6RkGP029840 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 13 Apr 2005 23:27:48 -0700 User-Agent: Mozilla Thunderbird 1.0.2-1.3.2 (X11/20050324) X-Accept-Language: en-us, en To: Christopher Li In-Reply-To: <20050414024228.GC18655@64m.dyndns.org> X-Spam-Status: No, score=-5.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.0.2 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on terminus.zytor.com Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Christopher Li wrote: > > But if you write a large number of random files, when htree has three > levels index. htree will suffer on the effect that it dirty random block > very quickly, most block get dirty only contain one or two new entries. > Ext3 will choke on it due to the limited journal size. > > While non-index directory, new entry are very compact on the blocks. > So it end up dirty a lot less blocks, of course, lookup will suffer. > > Depend on you want check out fast or write a big tree fast, you can't > win it all. > Actually, the subdirectory hack has the same effect, so you lose regardless. Doesn't mean that you can't construct cases where the subdirectory hack doesn't win, but I maintain that those are likely to be artificial. It's probably worth noting that you have to assume htree is on, since that's the typical default for a Linux installation, even if you use the subdirectory hack. -hpa