From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: 1.3.0 creating bigger packs than 1.2.3 Date: Thu, 20 Apr 2006 09:07:21 -0700 (PDT) Message-ID: References: <20060420133640.GA31198@spearce.org> <20060420150315.GB31198@spearce.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: git@vger.kernel.org X-From: git-owner@vger.kernel.org Thu Apr 20 18:07:53 2006 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by ciao.gmane.org with esmtp (Exim 4.43) id 1FWbgv-000428-Fu for gcvg-git@gmane.org; Thu, 20 Apr 2006 18:07:38 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751031AbWDTQHe (ORCPT ); Thu, 20 Apr 2006 12:07:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751032AbWDTQHe (ORCPT ); Thu, 20 Apr 2006 12:07:34 -0400 Received: from smtp.osdl.org ([65.172.181.4]:9371 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751029AbWDTQHd (ORCPT ); Thu, 20 Apr 2006 12:07:33 -0400 Received: from shell0.pdx.osdl.net (fw.osdl.org [65.172.181.6]) by smtp.osdl.org (8.12.8/8.12.8) with ESMTP id k3KG7MtH018512 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Thu, 20 Apr 2006 09:07:23 -0700 Received: from localhost (shell0.pdx.osdl.net [10.9.0.31]) by shell0.pdx.osdl.net (8.13.1/8.11.6) with ESMTP id k3KG7LMP031332; Thu, 20 Apr 2006 09:07:22 -0700 To: Shawn Pearce In-Reply-To: <20060420150315.GB31198@spearce.org> X-Spam-Status: No, hits=0 required=5 tests= X-Spam-Checker-Version: SpamAssassin 2.63-osdl_revision__1.72__ X-MIMEDefang-Filter: osdl$Revision: 1.133 $ X-Scanned-By: MIMEDefang 2.36 Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Thu, 20 Apr 2006, Shawn Pearce wrote: > > So with 1.3.0.g56c1 "git repack -a -d -f" did worse: > > Total 46391, written 46391 (delta 6649), reused 39742 (delta 0) > 129M pack-7f766f5af5547554bacb28c0294bd562589dc5e7.pack > > I just tried -f on v1.2.3 and it did slightly better then before: > > Total 46391, written 46391 (delta 6847), reused 38012 (delta 0) > 59M pack-7f766f5af5547554bacb28c0294bd562589dc5e7.pack Interesting. The bigger packs do generate fewer deltas, but they don't seem to be _that_ much fewer. And the deltas themselves certainly shouldn't be bigger. It almost sounds like there's a problem with choosing what to delta against, not necessarily a delta algorithm problem. Although that sounds a bit strange, because I wouldn't have thought we actually changed the packing algorithm noticeably since 1.2.3. Hmm. Doing "gitk v1.2.3.. -- pack-objects.c" shows that I was wrong. Junio did the "hash basename and direname a bit differently" thing, which would appear to change the "find objects to delta against" a lot. That could be it. You could try to revert that change: git revert eeef7135fed9b8784627c4c96e125241c06c65e1 which needs a trivial manual fixup (remove the conflict entirely: everything between the "<<<<" and ">>>>>" lines should go), and see if that's it. You can also try to see if git repack -a -d -f --window=50 makes for a better pack (at the cost of a much slower repack). It makes git try more objects to delta against, and can thus hide a bad sort order. Junio, any other suggestions? Linus