From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id 21FD41F4B4 for ; Wed, 3 Feb 2021 20:06:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231638AbhBCUEv (ORCPT ); Wed, 3 Feb 2021 15:04:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231759AbhBCUEh (ORCPT ); Wed, 3 Feb 2021 15:04:37 -0500 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77666C06178B for ; Wed, 3 Feb 2021 12:03:53 -0800 (PST) Received: by mail-wr1-x430.google.com with SMTP id z6so652375wrq.10 for ; Wed, 03 Feb 2021 12:03:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:mime-version :content-transfer-encoding:fcc:to:cc; bh=yfDtjcJ1TJXIGMyNUMt1kQBPOnO99QJK9uriR9Vve44=; b=rRedbHH3047FMa9nZg+WVmrL9mP1GRNpwQFNdlVxsIywNohrXT6PVeGiQd/aCmHRpp qkxPZC+jLwOL6s1f1Nrua9SOZRFdcPgh9MB4xByO5KYsFCB/YjGvxsOKDGl6qhUUOyT9 vDkmAvVuISFqpaxzT0Klk0oWKz4oktI+Cmlg80wbKdkUuhyZWjxsi4Jy0eJRNHeQHxwq UAEZooa1KfmESOsG41/VdrKeNCeUbTZzc8YLrZn/4P5kjylwwGoDipAZCiDHLuEZa/Ve klew5ya13d7WZZkrYSI7eeAUWpnC52R/q5itjzIg8ve57OQk2kfSVrbeT9nNDje97xEn O3cQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:mime-version:content-transfer-encoding:fcc:to:cc; bh=yfDtjcJ1TJXIGMyNUMt1kQBPOnO99QJK9uriR9Vve44=; b=CQ4xLi/d1pOu3ZBptrzyeinMxmdC6H0RWJcy95/uP7QRn1SjpH9nJRkleFzsUVS/Wv u1dfLpxr0A2drYT7GEHi4gpgU3BhRb5CykSZA/rni5AS9yKMMItwueXNyvsY/r7S9b+j QxqNq7W7ay6ITzTmBdZEySTI7EnAdmsbrcRLUPByZAiiSIrUn/aF2ll7odnYt66ydAlG M73XNFrF20QlbIBg8oZl0Qc2ioIx0plY3fZd1AyEItfdQ1ODL55RVnfXSb9iCUyB/lIe C6Me1s7yroJZSNgVHxN+2hlaRpl9izNpmeGTyYRfQVQVFLuwYqRS5FKgl3KRjfc+yrRG hmLA== X-Gm-Message-State: AOAM532Ns9J/1MWfgTBO2FbCuzHJMcq5TodJoMfDNE5GyKhuNOwO6IQJ KXoQS8UdsuCT60mXbvLurwUEOPmSIi0= X-Google-Smtp-Source: ABdhPJxofSpWmJbaYd61CpmYnJOHK3VYUxaua6/SzMnYxZyPbtZ90FObG8276b75PPMDGeIpUwXf7w== X-Received: by 2002:a05:6000:1788:: with SMTP id e8mr5444700wrg.171.1612382632013; Wed, 03 Feb 2021 12:03:52 -0800 (PST) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id z1sm4970563wrp.62.2021.02.03.12.03.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Feb 2021 12:03:51 -0800 (PST) Message-Id: <7ae9460d3dba84122c2674b46e4339b9d42bdedd.1612382628.git.gitgitgadget@gmail.com> In-Reply-To: References: From: "Elijah Newren via GitGitGadget" Date: Wed, 03 Feb 2021 20:03:47 +0000 Subject: [PATCH v2 2/2] diffcore-rename: filter rename_src list when possible MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fcc: Sent To: git@vger.kernel.org Cc: Derrick Stolee , Jonathan Tan , Taylor Blau , Junio C Hamano , Jeff King , Karsten Blees , Derrick Stolee , Elijah Newren , Elijah Newren , Elijah Newren Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Elijah Newren We have to look at each entry in rename_src a total of rename_dst_nr times. When we're not detecting copies, any exact renames or ignorable rename paths will just be skipped over. While checking that these can be skipped over is a relatively cheap check, it's still a waste of time to do that check more than once, let alone rename_dst_nr times. When rename_src_nr is a few thousand times bigger than the number of relevant sources (such as when cherry-picking a commit that only touched a handful of files, but from a side of history that has different names for some high level directories), this time can add up. First make an initial pass over the rename_src array and move all the relevant entries to the front, so that we can iterate over just those relevant entries. For the testcases mentioned in commit 557ac0350d ("merge-ort: begin performance work; instrument with trace2_region_* calls", 2020-10-28), this change improves the performance as follows: Before After no-renames: 14.119 s ± 0.101 s 13.815 s ± 0.062 s mega-renames: 1802.044 s ± 0.828 s 1799.937 s ± 0.493 s just-one-mega: 51.391 s ± 0.028 s 51.289 s ± 0.019 s Signed-off-by: Elijah Newren --- diffcore-rename.c | 57 ++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 51 insertions(+), 6 deletions(-) diff --git a/diffcore-rename.c b/diffcore-rename.c index 8b118628b4e..74930716e70 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -454,6 +454,54 @@ static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, i return count; } +static void remove_unneeded_paths_from_src(int detecting_copies) +{ + int i, new_num_src; + + if (detecting_copies) + return; /* nothing to remove */ + if (break_idx) + return; /* culling incompatbile with break detection */ + + /* + * Note on reasons why we cull unneeded sources but not destinations: + * 1) Pairings are stored in rename_dst (not rename_src), which we + * need to keep around. So, we just can't cull rename_dst even + * if we wanted to. But doing so wouldn't help because... + * + * 2) There is a matrix pairwise comparison that follows the + * "Performing inexact rename detection" progress message. + * Iterating over the destinations is done in the outer loop, + * hence we only iterate over each of those once and we can + * easily skip the outer loop early if the destination isn't + * relevant. That's only one check per destination path to + * skip. + * + * By contrast, the sources are iterated in the inner loop; if + * we check whether a source can be skipped, then we'll be + * checking it N separate times, once for each destination. + * We don't want to have to iterate over known-not-needed + * sources N times each, so avoid that by removing the sources + * from rename_src here. + */ + for (i = 0, new_num_src = 0; i < rename_src_nr; i++) { + /* + * renames are stored in rename_dst, so if a rename has + * already been detected using this source, we can just + * remove the source knowing rename_dst has its info. + */ + if (rename_src[i].p->one->rename_used) + continue; + + if (new_num_src < i) + memcpy(&rename_src[new_num_src], &rename_src[i], + sizeof(struct diff_rename_src)); + new_num_src++; + } + + rename_src_nr = new_num_src; +} + void diffcore_rename(struct diff_options *options) { int detect_rename = options->detect_rename; @@ -530,13 +578,11 @@ void diffcore_rename(struct diff_options *options) goto cleanup; /* - * Calculate how many renames are left (but all the source - * files still remain as options for rename/copies!) + * Calculate how many renames are left */ num_destinations = (rename_dst_nr - rename_count); + remove_unneeded_paths_from_src(want_copies); num_sources = rename_src_nr; - if (!want_copies) - num_sources -= rename_count; /* All done? */ if (!num_destinations || !num_sources) @@ -578,8 +624,7 @@ void diffcore_rename(struct diff_options *options) struct diff_filespec *one = rename_src[j].p->one; struct diff_score this_src; - if (one->rename_used && !want_copies) - continue; + assert(!one->rename_used || want_copies || break_idx); if (skip_unmodified && diff_unmodified_pair(rename_src[j].p)) -- gitgitgadget