From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-2.8 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,T_DKIM_INVALID, T_RP_MATCHES_RCVD shortcircuit=no autolearn=no autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 6896F1F404 for ; Tue, 6 Mar 2018 19:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933312AbeCFTau (ORCPT ); Tue, 6 Mar 2018 14:30:50 -0500 Received: from mail-wr0-f176.google.com ([209.85.128.176]:36436 "EHLO mail-wr0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753560AbeCFT3q (ORCPT ); Tue, 6 Mar 2018 14:29:46 -0500 Received: by mail-wr0-f176.google.com with SMTP id v111so22116522wrb.3 for ; Tue, 06 Mar 2018 11:29:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:references:date:in-reply-to:message-id :user-agent:mime-version; bh=7xDn64toh3heXf9xomSJe2/3G4zfnFPlqx9NSPFIOjg=; b=WD4PyvaJgmZJvzQBgR744c+ohU0hT4INU52EKIjvyPcxroksaxjigFrxmdQkBaZnKf nD2BBCtD9jwfOivVX0xgcH9vyM+hPuVFqK5jYC1b8fJySpeuiaGtdwx6Uvm5eOpyYwFd ANn2r99G7HNNNIJ1dCGeiJEIryx36+sO/QIlBu58pNPaPv7lpvOE7ZWEGp0l/hbToVFU /JYjUSEK7w8yFY7JTSvf746mFhpqW0MJOWEbBAPH9mwPxUG0xu0xs6wEY0eeun1qPDTQ SPD7byvdArM1JVWsNl6/oNtb6ep+rPqf6ilYQOQrurYQ+tvseAHnMlT9svUD/AL4Tq6g iK/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:references:date :in-reply-to:message-id:user-agent:mime-version; bh=7xDn64toh3heXf9xomSJe2/3G4zfnFPlqx9NSPFIOjg=; b=BZK8Lc5DnyWRCJ756xHCjV5snyEIynVt4b6Zj6qckBSF5GwSnTXINA6NuZ9wN8Go6u zFijFfVxbRdG1gnuwQZUFYdF/Py36/KzhpQqKUcSRd7htvAFxw296dXtdOM9ezgcuja4 MS3+2+NPjk2eNw0/BWfN6jhlcIJKYDbDGH2JHDsMZRw4u35AVpQLFPgtV70QBzOyiwyc qrk7ELmdw9z6AvaEEJ/Q5VlT+ptlFSmluDR6f8wgGcL+TxAzU4KE6ltXwbzRT8S4RuZ/ 4PPgAS6XvMpW+n6EOKwY4bCT4irVI5UeyQ1Fun2Ca0vpeu0bxMNfRz/WmMLz7UdzFrJz 2SVQ== X-Gm-Message-State: APf1xPBJIM6Al5XSutBKZoihsJfzfHtuyv1WNSLgpgVe1Ixr9wK7mJyV gXUKfBKQrRkb4HJGk0mUWDU= X-Google-Smtp-Source: AG47ELsB5hvQJA2pcOgsbdg7nzexNTVK8t/IxVrRyZpxHlOY0GylEKZc8xIlp/V5koISQM7CHN2pnw== X-Received: by 10.223.128.201 with SMTP id 67mr16475807wrl.131.1520364585300; Tue, 06 Mar 2018 11:29:45 -0800 (PST) Received: from localhost (168.50.187.35.bc.googleusercontent.com. [35.187.50.168]) by smtp.gmail.com with ESMTPSA id 4sm8775141wmz.31.2018.03.06.11.29.44 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 06 Mar 2018 11:29:44 -0800 (PST) From: Junio C Hamano To: Eric Sunshine Cc: Jun Wu , git Subject: Re: [PATCH] xdiff: improve trimming preprocessing References: <1520337165-sup-4504@x1c> Date: Tue, 06 Mar 2018 11:29:44 -0800 In-Reply-To: (Eric Sunshine's message of "Tue, 6 Mar 2018 14:23:46 -0500") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Eric Sunshine writes: > On Tue, Mar 6, 2018 at 6:53 AM, Jun Wu wrote: >> xdiff-interface trims common suffix if ctxlen is 0. Teach it to also >> trim common prefix, and trim less lines if ctxlen > 0. So it can benefit >> the default diff command, as seen by profiling: [...] I vaguely recall that we have tried this in the distant past, found that it produced incorrect result, and that is why we limit the optimization for no-context case. Does anybody have an archive reference?