From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Hommey Subject: Re: absurdly slow git-diff Date: Fri, 7 Nov 2008 22:28:36 +0100 Organization: glandium.org Message-ID: <20081107212836.GA22717@glandium.org> References: <20081107200126.GA20284@toroid.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org To: Abhijit Menon-Sen X-From: git-owner@vger.kernel.org Fri Nov 07 22:30:01 2008 connect(): Connection refused Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1KyYu0-0003Sd-Jv for gcvg-git-2@gmane.org; Fri, 07 Nov 2008 22:30:01 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751388AbYKGV2q (ORCPT ); Fri, 7 Nov 2008 16:28:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751345AbYKGV2q (ORCPT ); Fri, 7 Nov 2008 16:28:46 -0500 Received: from vuizook.err.no ([194.24.252.247]:38813 "EHLO vuizook.err.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750816AbYKGV2p (ORCPT ); Fri, 7 Nov 2008 16:28:45 -0500 Received: from cha92-13-88-165-248-19.fbx.proxad.net ([88.165.248.19] helo=jigen) by vuizook.err.no with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.69) (envelope-from ) id 1KyYsg-0002KD-GE; Fri, 07 Nov 2008 22:28:41 +0100 Received: from mh by jigen with local (Exim 4.69) (envelope-from ) id 1KyYse-0006MA-QE; Fri, 07 Nov 2008 22:28:36 +0100 Content-Disposition: inline In-Reply-To: <20081107200126.GA20284@toroid.org> X-GPG-Fingerprint: A479 A824 265C B2A5 FC54 8D1E DE4B DA2C 54FD 2A58 User-Agent: Mutt/1.5.18 (2008-05-17) X-Spam-Status: (score 0.1): No, score=0.1 required=5.0 tests=RDNS_DYNAMIC autolearn=disabled version=3.2.4 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Sat, Nov 08, 2008 at 01:31:27AM +0530, Abhijit Menon-Sen wrote: > I have a 240k-line file, and I change one character on every sixth line. > The resulting diff gives git serious indigestion: > > $ git --version > git version 1.6.0.3.640.g6331a > $ mkdir a; cd a; git init > Initialized empty Git repository in /home/ams/a/.git/ > $ cp ../1 .; git add 1; git commit -q -m 1 > $ cp ../2 1; git add 1; git commit -q -m 2 You don't need to go that far. You can stop at cp ../2 1 and run git diff from there. All the time is spent in the two loops in xdiff/xprepare.c:xdl_cleanup_records, on line 400 and 412. I'll leave the rest of the investigation to people actually knowing this code ;) Mike