From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Pearce Subject: Re: Mozilla .git tree Date: Sat, 2 Sep 2006 13:44:32 -0400 Message-ID: <20060902174432.GB27826@spearce.org> References: <20060830015122.GE22935@spearce.org> <9e4733910608291958l45c0257dla6e5ebd4176f7164@mail.gmail.com> <20060830031029.GA23967@spearce.org> <7vzmdmh2lu.fsf@assigned-by-dhcp.cox.net> <7vr6yw58xp.fsf@assigned-by-dhcp.cox.net> <20060902011950.GB24234@spearce.org> <7v8xl23oia.fsf@assigned-by-dhcp.cox.net> <20060902043931.GA25146@spearce.org> <7vveo6zfx0.fsf@assigned-by-dhcp.cox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org X-From: git-owner@vger.kernel.org Sun Sep 03 11:27:55 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 1GJoGe-0005cu-FP for gcvg-git@gmane.org; Sun, 03 Sep 2006 11:27:52 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751045AbWICJ1f (ORCPT ); Sun, 3 Sep 2006 05:27:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750917AbWICJ1f (ORCPT ); Sun, 3 Sep 2006 05:27:35 -0400 Received: from corvette.plexpod.net ([64.38.20.226]:22232 "EHLO corvette.plexpod.net") by vger.kernel.org with ESMTP id S1751293AbWIBTK4 (ORCPT ); Sat, 2 Sep 2006 15:10:56 -0400 Received: from cpe-74-70-48-173.nycap.res.rr.com ([74.70.48.173] helo=asimov.home.spearce.org) by corvette.plexpod.net with esmtpa (Exim 4.52) id 1GJat7-0007oP-GJ; Sat, 02 Sep 2006 15:10:47 -0400 Received: by asimov.home.spearce.org (Postfix, from userid 1000) id C415520FB7C; Sat, 2 Sep 2006 13:44:32 -0400 (EDT) To: Junio C Hamano Content-Disposition: inline In-Reply-To: <7vveo6zfx0.fsf@assigned-by-dhcp.cox.net> User-Agent: Mutt/1.5.11 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - corvette.plexpod.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [0 0] / [47 12] X-AntiAbuse: Sender Address Domain - spearce.org X-Source: X-Source-Args: X-Source-Dir: Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: Junio C Hamano wrote: > Shawn Pearce writes: > > > Using a 28 byte index entry instead of a 32 byte index entry means > > the Mozilla historical pack index will only be 52.4 MiB rather than > > the slightly larger 59.9 MiB. > > Yup, that was one consideration. One small worry is we will be > placing u64 at 4-byte alignment by using 28-byte entries but I > think that is Ok. On some systems (SPARC?) that's definately an issue. Other systems (x86) obviously don't have that problem. If you code the decode function as treating that 64 bit value as two 32 bit values in network byte order and combine them together after ntohl() then this shouldn't be a problem. Though big-endian systems which can take a u64 on a 4-byte alignment just fine would pay a small performance penalty that they don't need to pay. -- Shawn. -- VGER BF report: S 0.998672