From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Pitre Subject: Re: [PATCH] add the ability to create and retrieve delta objects Date: Wed, 04 May 2005 23:10:47 -0400 (EDT) Message-ID: References: <200505030657.38309.alonz@nolaviz.org> <200505041156.19499.mason@suse.com> <200505041834.19053.mason@suse.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Transfer-Encoding: 7BIT Cc: Geert Bosch , Linus Torvalds , Alon Ziv , git@vger.kernel.org X-From: git-owner@vger.kernel.org Thu May 05 05:05:04 2005 Return-path: Received: from vger.kernel.org ([12.107.209.244]) by ciao.gmane.org with esmtp (Exim 4.43) id 1DTWfY-0002lv-Ak for gcvg-git@gmane.org; Thu, 05 May 2005 05:04:56 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262009AbVEEDLO (ORCPT ); Wed, 4 May 2005 23:11:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262010AbVEEDLO (ORCPT ); Wed, 4 May 2005 23:11:14 -0400 Received: from relais.videotron.ca ([24.201.245.36]:13237 "EHLO relais.videotron.ca") by vger.kernel.org with ESMTP id S262009AbVEEDKv (ORCPT ); Wed, 4 May 2005 23:10:51 -0400 Received: from xanadu.home ([24.200.213.96]) by VL-MO-MR007.ip.videotron.ca (iPlanet Messaging Server 5.2 HotFix 1.21 (built Sep 8 2003)) with ESMTP id <0IFZ00D74Y5Z4P@VL-MO-MR007.ip.videotron.ca> for git@vger.kernel.org; Wed, 04 May 2005 23:10:47 -0400 (EDT) In-reply-to: <200505041834.19053.mason@suse.com> X-X-Sender: nico@localhost.localdomain To: Chris Mason Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org On Wed, 4 May 2005, Chris Mason wrote: > On Wednesday 04 May 2005 17:47, Geert Bosch wrote: > > From your tests it would seem that the zdelta version is the only one > > to provide a uniform improvement over plain git. As it also seems the > > simplest approach, I wonder why the consensus is that using xdiff > > would be better? > > zdelta seems to be a research project. It does compress better than the xdiff > lib, but the speed improvements against xdiff(1) are probably because the > resulting tree is smaller. I favor the xdiff code because it's so much > smaller, and seems easier for us to maintain. Yep. And compression can be improved without changing de decompressor since the decompressor is only a replay of what the compressor found to be redundent. That redundency searching can probably be improved wrt to the current code. And FRankly considering about 300 lines of code to create a delta and 60 lines to expand it is hard to beat maintenance wise. > For performance, there's still quite a bit of tuning that can be done in terms > of when and how we delta. Indeed. Nicolas