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-ASN: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-4.0 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,RCVD_IN_DNSWL_LOW, 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 4C5F51F9F4 for ; Tue, 15 Jun 2021 22:42:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230486AbhFOWoF (ORCPT ); Tue, 15 Jun 2021 18:44:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230413AbhFOWn7 (ORCPT ); Tue, 15 Jun 2021 18:43:59 -0400 Received: from mail-wm1-x32b.google.com (mail-wm1-x32b.google.com [IPv6:2a00:1450:4864:20::32b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84366C06175F for ; Tue, 15 Jun 2021 15:41:53 -0700 (PDT) Received: by mail-wm1-x32b.google.com with SMTP id b205so63602wmb.3 for ; Tue, 15 Jun 2021 15:41:53 -0700 (PDT) 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:fcc :content-transfer-encoding:mime-version:to:cc; bh=YIf9ji05trrJItCTvVz7rkhv84p83dJwpdFScY8oKRk=; b=keSi2tAjGk0ReGru5DD0tK1lmDZIgE8URZRo5juon7FWjwr+w1HAjUf3DJ84shM0TP 7h48DJWwWWvEUQWmSwmZolj2dhJm1NywzIIvbBvm67dKr3+UcWVHrdTtLQizXrknkIwf m9+0Q6Ev+4mFJ0vLPCjGco7TlqJ4/g3QaqZgtfMaXPNskvJyyekTfEyyzE53a+aOu1Wr N0hov07dFw8YU1fnbNKsH9cmeFKGsHaRD888hIqUeQkrRd9yryRbzRIcvb6vLBJPZYSr EvH6QDBr+kleck57whY1acVnGxOLC63/+ifobq2xITEyd57VP9bv7tFO8MYc65plEwcb VCqw== 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:fcc:content-transfer-encoding:mime-version:to:cc; bh=YIf9ji05trrJItCTvVz7rkhv84p83dJwpdFScY8oKRk=; b=DlyGB6AUqS2o0WQ7UxaD/UiIme3nYmd+owvnw5t8n22O7kcRaN8dfhmSm+X66ggaEN fBDDRwA0lgJV18Ql8NIHXBNVfUBdlHiuMMyu9mHd/pBDrwMq+TzSMLEsR8GolPf5sUYN xsqjyWGSB3KRzVG8i4rbFukh2lGwElBBc0W+4GMTa5HqC1vWilvWR5blijG3Wz6fj7Ss l6rX4PFcDy8EMPkydxvNQ7NUhl0rio14A1g33AsTsubHC+3qi6jFUcPxgwkIa1RWeJlV 0tylvi+5sH2N6E9NVfS5/2dN6U2voZB47sHWX74bDHjcx0BbaGWfvFwiEX4KY+0QZTU3 y1lw== X-Gm-Message-State: AOAM531TPoiL0AiQuCBk7Jzn4V8N4k8UQ1BmhsbDwCIM/9G+pT6U84b2 CYd5mICwDQfYa335cOuSjk5FaBl9uWs= X-Google-Smtp-Source: ABdhPJzYiv9lU1cWzlmnCMqu8CR0al9EQr0+XhXFz9vOlh+qeV/eV04i0kKi4UuFg4TW09nDXss9Gg== X-Received: by 2002:a1c:61d6:: with SMTP id v205mr1665253wmb.143.1623796912173; Tue, 15 Jun 2021 15:41:52 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id x3sm3366613wmj.30.2021.06.15.15.41.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Jun 2021 15:41:51 -0700 (PDT) Message-Id: <317bcc7f56cb718a8be625838576f33ce788c3ef.1623796907.git.gitgitgadget@gmail.com> In-Reply-To: References: From: "Elijah Newren via GitGitGadget" Date: Tue, 15 Jun 2021 22:41:46 +0000 Subject: [PATCH v2 5/5] merge-ort: add prefetching for content merges Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 To: git@vger.kernel.org Cc: Jonathan Tan , Derrick Stolee , Taylor Blau , Elijah Newren , Elijah Newren Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Elijah Newren Commit 7fbbcb21b1 ("diff: batch fetching of missing blobs", 2019-04-05) introduced batching of fetching missing blobs, so that the diff machinery would have one fetch subprocess grab N blobs instead of N processes each grabbing 1. However, the diff machinery is not the only thing in a merge that needs to work on blobs. The 3-way content merges need them as well. Rather than download all the blobs 1 at a time, prefetch all the blobs needed for regular content merges. This does not cover all possible paths in merge-ort that might need to download blobs. Others include: - The blob_unchanged() calls to avoid modify/delete conflicts (when blob renormalization results in an "unchanged" file) - Preliminary content merges needed for rename/add and rename/rename(2to1) style conflicts. (Both of these types of conflicts can result in nested conflict markers from the need to do two levels of content merging; the first happens before our new prefetch_for_content_merges() function.) The first of these wouldn't be an extreme amount of work to support, and even the second could be theoretically supported in batching, but all of these cases seem unusual to me, and this is a minor performance optimization anyway; in the worst case we only get some of the fetches batched and have a few additional one-off fetches. So for now, just handle the regular 3-way content merges in our prefetching. For the testcase from the previous commit, the number of downloaded objects remains at 63, but this drops the number of fetches needed from 32 down to 20, a sizeable reduction. Signed-off-by: Elijah Newren --- merge-ort.c | 50 ++++++++++++++++++++++++++++++++++ t/t6421-merge-partial-clone.sh | 2 +- 2 files changed, 51 insertions(+), 1 deletion(-) diff --git a/merge-ort.c b/merge-ort.c index cfa751053b01..e3a5dfc7b312 100644 --- a/merge-ort.c +++ b/merge-ort.c @@ -29,6 +29,7 @@ #include "entry.h" #include "ll-merge.h" #include "object-store.h" +#include "promisor-remote.h" #include "revision.h" #include "strmap.h" #include "submodule.h" @@ -3485,6 +3486,54 @@ static void process_entry(struct merge_options *opt, record_entry_for_tree(dir_metadata, path, &ci->merged); } +static void prefetch_for_content_merges(struct merge_options *opt, + struct string_list *plist) +{ + struct string_list_item *e; + struct oid_array to_fetch = OID_ARRAY_INIT; + + if (opt->repo != the_repository || !has_promisor_remote()) + return; + + for (e = &plist->items[plist->nr-1]; e >= plist->items; --e) { + /* char *path = e->string; */ + struct conflict_info *ci = e->util; + int i; + + /* Ignore clean entries */ + if (ci->merged.clean) + continue; + + /* Ignore entries that don't need a content merge */ + if (ci->match_mask || ci->filemask < 6 || + !S_ISREG(ci->stages[1].mode) || + !S_ISREG(ci->stages[2].mode) || + oideq(&ci->stages[1].oid, &ci->stages[2].oid)) + continue; + + /* Also don't need content merge if base matches either side */ + if (ci->filemask == 7 && + S_ISREG(ci->stages[0].mode) && + (oideq(&ci->stages[0].oid, &ci->stages[1].oid) || + oideq(&ci->stages[0].oid, &ci->stages[2].oid))) + continue; + + for (i = 0; i < 3; i++) { + unsigned side_mask = (1 << i); + struct version_info *vi = &ci->stages[i]; + + if ((ci->filemask & side_mask) && + S_ISREG(vi->mode) && + oid_object_info_extended(opt->repo, &vi->oid, NULL, + OBJECT_INFO_FOR_PREFETCH)) + oid_array_append(&to_fetch, &vi->oid); + } + } + + promisor_remote_get_direct(opt->repo, to_fetch.oid, to_fetch.nr); + oid_array_clear(&to_fetch); +} + static void process_entries(struct merge_options *opt, struct object_id *result_oid) { @@ -3531,6 +3580,7 @@ static void process_entries(struct merge_options *opt, * the way when it is time to process the file at the same path). */ trace2_region_enter("merge", "processing", opt->repo); + prefetch_for_content_merges(opt, &plist); for (entry = &plist.items[plist.nr-1]; entry >= plist.items; --entry) { char *path = entry->string; /* diff --git a/t/t6421-merge-partial-clone.sh b/t/t6421-merge-partial-clone.sh index a011f8d27867..26964aa56256 100755 --- a/t/t6421-merge-partial-clone.sh +++ b/t/t6421-merge-partial-clone.sh @@ -396,7 +396,7 @@ test_expect_merge_algorithm failure success 'Objects downloaded when a directory # # Summary: 4 fetches (1 for 6 objects, 1 for 8, 1 for 3, 1 for 2) # -test_expect_merge_algorithm failure failure 'Objects downloaded with lots of renames and modifications' ' +test_expect_merge_algorithm failure success 'Objects downloaded with lots of renames and modifications' ' test_setup_repo && git clone --sparse --filter=blob:none "file://$(pwd)/server" objects-many && ( -- gitgitgadget