From patchwork Fri Sep 25 12:33:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philippe Blain via GitGitGadget X-Patchwork-Id: 11799685 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 99A146CB for ; Fri, 25 Sep 2020 12:33:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7480F21D91 for ; Fri, 25 Sep 2020 12:33:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YSKwtzso" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728414AbgIYMdv (ORCPT ); Fri, 25 Sep 2020 08:33:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbgIYMds (ORCPT ); Fri, 25 Sep 2020 08:33:48 -0400 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7692FC0613CE for ; Fri, 25 Sep 2020 05:33:48 -0700 (PDT) Received: by mail-wr1-x443.google.com with SMTP id w5so3404878wrp.8 for ; Fri, 25 Sep 2020 05:33:48 -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=mLlzQzqhmLMuWlvzwdcUhGaHdx1mdNT/YofPN6ovyOY=; b=YSKwtzsoxaoxM0DkOJZXFgVR+d5uTM/LaMLU+2Kh/Z8KlJtwKnDo4va2IvfoJu5049 NDgvmWRmwcHWWLTM1bf59SKMo2F43zalhUYhLP0PSg/U+CCLA4NfKQg7z1wpMKzaGDVD N95C5h/+5zj5M/B9Lp8RkItawhkyUJqT145EMQuh69VrdfBMG53xN0ecNXiby7k/CALs e7uBN+62sV6M10aq3NYSd6SXwuzGaGBdsgMlY384rDucdkatqTR+G/mdgHAAs9DgsKP8 w0W2ue01IGpewBSVdsNHEnPovYj/77DOkAPDac0JpuF0mI9Be9cnszhS9d9LiKa1Eakk NJbA== 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=mLlzQzqhmLMuWlvzwdcUhGaHdx1mdNT/YofPN6ovyOY=; b=LdJzBFrIGlE6BdgnBxJEZZSyzah+N2CJpqcIfz/R0TXeb/FiLOl3qGCxTx382lmvNI Xc0q37f9+7zU1siUzlVtQBOBEy8YYiyUV84+SYbvzVXDaFBM1kGq5/+P4PHnB6nWQUgg YHnnSN1g4cN0DCpNXG0lmF3ZsjW2pfqUbNN3iJT5PLesakAdGjLi9m7bIEmI689WFFBu fWaLvVsxugZzE2+KSdOPhd0fbtPBGfsSgeBKvSvK/TIKfL9kQ9AeHL8WuHIVuRjyNZEK pkJzPht4QRN+by33/L+86LeVHX/raQ5Vov6lKPZp7cJrnRjsBO8dGv0MTEF3gKQat4wm zt8g== X-Gm-Message-State: AOAM531kG4j4GXWvP/KwM5H0cBWs/V+AMVICb9vGrVuCyNeOJcqsVSha jNAB1XF//m4NK8A3buJ5SdQ/hc04Cu4= X-Google-Smtp-Source: ABdhPJx5l8lG7AH9kdLPpC/FIGLxZ6ClmlOLU5LiqbUo5vcXV8kpmJJOmqQ26x8zHfIWc9QLegCbuw== X-Received: by 2002:adf:c3cc:: with SMTP id d12mr4315341wrg.399.1601037226987; Fri, 25 Sep 2020 05:33:46 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id o4sm2705373wrv.86.2020.09.25.05.33.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Sep 2020 05:33:46 -0700 (PDT) Message-Id: In-Reply-To: References: From: "Derrick Stolee via GitGitGadget" Date: Fri, 25 Sep 2020 12:33:37 +0000 Subject: [PATCH v4 7/8] maintenance: auto-size incremental-repack batch Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: sandals@crustytoothpaste.net, steadmon@google.com, jrnieder@gmail.com, peff@peff.net, congdanhqx@gmail.com, phillip.wood123@gmail.com, emilyshaffer@google.com, sluongng@gmail.com, jonathantanmy@google.com, Jonathan Tan , Derrick Stolee , Derrick Stolee , Derrick Stolee Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Derrick Stolee When repacking during the 'incremental-repack' task, we use the --batch-size option in 'git multi-pack-index repack'. The initial setting used --batch-size=0 to repack everything into a single pack-file. This is not sustainable for a large repository. The amount of work required is also likely to use too many system resources for a background job. Update the 'incremental-repack' task by dynamically computing a --batch-size option based on the current pack-file structure. The dynamic default size is computed with this idea in mind for a client repository that was cloned from a very large remote: there is likely one "big" pack-file that was created at clone time. Thus, do not try repacking it as it is likely packed efficiently by the server. Instead, we select the second-largest pack-file, and create a batch size that is one larger than that pack-file. If there are three or more pack-files, then this guarantees that at least two will be combined into a new pack-file. Of course, this means that the second-largest pack-file size is likely to grow over time and may eventually surpass the initially-cloned pack-file. Recall that the pack-file batch is selected in a greedy manner: the packs are considered from oldest to newest and are selected if they have size smaller than the batch size until the total selected size is larger than the batch size. Thus, that oldest "clone" pack will be first to repack after the new data creates a pack larger than that. We also want to place some limits on how large these pack-files become, in order to bound the amount of time spent repacking. A maximum batch-size of two gigabytes means that large repositories will never be packed into a single pack-file using this job, but also that repack is rather expensive. This is a trade-off that is valuable to have if the maintenance is being run automatically or in the background. Users who truly want to optimize for space and performance (and are willing to pay the upfront cost of a full repack) can use the 'gc' task to do so. Create a test for this two gigabyte limit by creating an EXPENSIVE test that generates two pack-files of roughly 2.5 gigabytes in size, then performs an incremental repack. Check that the --batch-size argument in the subcommand uses the hard-coded maximum. Helped-by: Chris Torek Reported-by: Son Luong Ngoc Signed-off-by: Derrick Stolee --- builtin/gc.c | 43 +++++++++++++++++++++++++++++++++++++++++- t/t7900-maintenance.sh | 36 +++++++++++++++++++++++++++++++++-- 2 files changed, 76 insertions(+), 3 deletions(-) diff --git a/builtin/gc.c b/builtin/gc.c index 5f877b097a..8d22361fa9 100644 --- a/builtin/gc.c +++ b/builtin/gc.c @@ -1035,6 +1035,46 @@ static int multi_pack_index_expire(struct maintenance_run_opts *opts) return 0; } +#define TWO_GIGABYTES (INT32_MAX) + +static off_t get_auto_pack_size(void) +{ + /* + * The "auto" value is special: we optimize for + * one large pack-file (i.e. from a clone) and + * expect the rest to be small and they can be + * repacked quickly. + * + * The strategy we select here is to select a + * size that is one more than the second largest + * pack-file. This ensures that we will repack + * at least two packs if there are three or more + * packs. + */ + off_t max_size = 0; + off_t second_largest_size = 0; + off_t result_size; + struct packed_git *p; + struct repository *r = the_repository; + + reprepare_packed_git(r); + for (p = get_all_packs(r); p; p = p->next) { + if (p->pack_size > max_size) { + second_largest_size = max_size; + max_size = p->pack_size; + } else if (p->pack_size > second_largest_size) + second_largest_size = p->pack_size; + } + + result_size = second_largest_size + 1; + + /* But limit ourselves to a batch size of 2g */ + if (result_size > TWO_GIGABYTES) + result_size = TWO_GIGABYTES; + + return result_size; +} + static int multi_pack_index_repack(struct maintenance_run_opts *opts) { struct child_process child = CHILD_PROCESS_INIT; @@ -1045,7 +1085,8 @@ static int multi_pack_index_repack(struct maintenance_run_opts *opts) if (opts->quiet) strvec_push(&child.args, "--no-progress"); - strvec_push(&child.args, "--batch-size=0"); + strvec_pushf(&child.args, "--batch-size=%"PRIuMAX, + (uintmax_t)get_auto_pack_size()); close_object_store(the_repository->objects); diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh index a2db2291b0..9e6ea23f35 100755 --- a/t/t7900-maintenance.sh +++ b/t/t7900-maintenance.sh @@ -181,10 +181,42 @@ test_expect_success 'incremental-repack task' ' test_line_count = 4 packs-between && # the job deletes the two old packs, and does not write - # a new one because only one pack remains. + # a new one because the batch size is not high enough to + # pack the largest pack-file. git maintenance run --task=incremental-repack && ls .git/objects/pack/*.pack >packs-after && - test_line_count = 1 packs-after + test_line_count = 2 packs-after +' + +test_expect_success EXPENSIVE 'incremental-repack 2g limit' ' + for i in $(test_seq 1 5) + do + test-tool genrandom foo$i $((512 * 1024 * 1024 + 1)) >>big || + return 1 + done && + git add big && + git commit -m "Add big file (1)" && + + # ensure any possible loose objects are in a pack-file + git maintenance run --task=loose-objects && + + rm big && + for i in $(test_seq 6 10) + do + test-tool genrandom foo$i $((512 * 1024 * 1024 + 1)) >>big || + return 1 + done && + git add big && + git commit -m "Add big file (2)" && + + # ensure any possible loose objects are in a pack-file + git maintenance run --task=loose-objects && + + # Now run the incremental-repack task and check the batch-size + GIT_TRACE2_EVENT="$(pwd)/run-2g.txt" git maintenance run \ + --task=incremental-repack 2>/dev/null && + test_subcommand git multi-pack-index repack \ + --no-progress --batch-size=2147483647