From patchwork Wed Aug 5 17:02:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Taylor Blau X-Patchwork-Id: 11701959 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 CE0DC1575 for ; Wed, 5 Aug 2020 17:05:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9EFB022D2C for ; Wed, 5 Aug 2020 17:05:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ttaylorr-com.20150623.gappssmtp.com header.i=@ttaylorr-com.20150623.gappssmtp.com header.b="dsrKHeRk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728371AbgHERFQ (ORCPT ); Wed, 5 Aug 2020 13:05:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728295AbgHERCu (ORCPT ); Wed, 5 Aug 2020 13:02:50 -0400 Received: from mail-qv1-xf43.google.com (mail-qv1-xf43.google.com [IPv6:2607:f8b0:4864:20::f43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 306A5C06174A for ; Wed, 5 Aug 2020 10:02:50 -0700 (PDT) Received: by mail-qv1-xf43.google.com with SMTP id s15so16636001qvv.7 for ; Wed, 05 Aug 2020 10:02:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ttaylorr-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=UkG0VbkkbfTo4r4sgGsVzU492HVkMStyXADq+pBNjSA=; b=dsrKHeRkGZ/QNV2n8Ty9sR8PykZVu4RmCDk9pn+67CvxTgGpQ7vukS2LRI5UuauTG7 R891fjQxjyd/caQfu1gIjuVn0J6E23YaqzI2XRMTdcXe5r17M6mJe+hx+N6MuclcaWGB 6zpAehs8HYQNTg4vd4u6BhRO1YbpcZkbdzoXwuBQEpC1ROMOearB3XhpnKRUwMABrGZJ I3jYGAVc2dXtodGBBnYoh2pIGAbD82cYlYHJNP0/jf0BHWCd3B/rlSCwaXX4mnJHQ8hq u9UF4Q8XjXvDKp63jpyC9/15H8YNW1N213LDbUTGjWaXjX3Q6zM9xZ9lx4U/qBaDH4f4 MjOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=UkG0VbkkbfTo4r4sgGsVzU492HVkMStyXADq+pBNjSA=; b=iyAqc2GK6MzmstIKSG9M9twtk6bPXhLZ3n+Y2B8nvCFwBpMvBVr7HuqcVIiS24f0pG hlR5Zq7Ooudg0PgyrhjyZkCk1jGw2WZkcGeLzTSzTixlzSObFl8TyJUD+8iruwiXJ+bG WDuLBen7s1Am72/9kXM4AtRkiLHsndv9QlfqOUpI47x+fczV17xpxBl331vKKmUaactw aHdfKsJdukH3RrfM2ZkSoaT2uZt6Jir0E8olq8EFU5AEMqiIFkUdzHF0XJrWIMPFFPc+ U0CW1b4gIrka4I2pzTuBp45Cvt/chDxlz53RIXDLbyvXBkho7IXX4Zb5M8zf1TCzTDVC knug== X-Gm-Message-State: AOAM531g0d2h520CNSVQaPDOXN55kNA6uW/HYCJOS7hcF40yDaOzPFn3 P73aPpLI8AiAjH6wjteTquv0M6OEcL6vMQ== X-Google-Smtp-Source: ABdhPJwU+tRnqHfbY1UdHaWepOuKgg2OhO9BBqpRhQnAYjOaDaqtB55A34Zv0TUooYAMdbF7er1TAQ== X-Received: by 2002:ad4:5388:: with SMTP id i8mr4627901qvv.202.1596646968683; Wed, 05 Aug 2020 10:02:48 -0700 (PDT) Received: from localhost ([2605:9480:22e:ff10:d118:9acc:fdba:dee7]) by smtp.gmail.com with ESMTPSA id q29sm2636272qtc.10.2020.08.05.10.02.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Aug 2020 10:02:47 -0700 (PDT) Date: Wed, 5 Aug 2020 13:02:47 -0400 From: Taylor Blau To: git@vger.kernel.org Cc: peff@peff.net, dstolee@microsoft.com, szeder.dev@gmail.com Subject: [PATCH v2 09/14] bloom/diff: properly short-circuit on max_changes Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Derrick Stolee Commit e3696980 (diff: halt tree-diff early after max_changes, 2020-03-30) intended to create a mechanism to short-circuit a diff calculation after a certain number of paths were modified. By incrementing a "num_changes" counter throughout the recursive ll_diff_tree_paths(), this was supposed to match the number of changes that would be written into the changed-path Bloom filters. Unfortunately, this was not implemented correctly and instead misses simple cases like file modifications. This then does not stop very large changed-path filters from being written (unless they add or remove many files). To start, change the implementation in ll_diff_tree_paths() to instead use the global diff_queue_diff struct's 'nr' member as the count. This is a way to simplify the logic instead of making more mistakes in the complicated diff code. This has a drawback: the diff_queue_diff struct only lists the paths corresponding to blob changes, not their leading directories. Thus, get_or_compute_bloom_filter() needs an additional check to see if the hashmap with the leading directories becomes too large. One reason why this was not caught by test cases was that the test in t4216-log-bloom.sh that was supposed to check this "too many changes" condition only checked this on the initial commit of a repository. The old logic counted these values correctly. Update this test in a few ways: 1. Use GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS to reduce the limit, allowing smaller commits to engage with this logic. 2. Create several interesting cases of edits, adds, removes, and mode changes (in the second commit). By testing both sides of the inequality with the *_MAX_CHANGED_PATHS variable, we can see that the count is exactly correct, so none of these changes are missed or over-counted. 3. Use the trace2 data value filter_found_large to verify that these commits are on the correct side of the limit. Another way to verify the behavior is correct is through performance tests. By testing on my local copies of the Git repository and the Linux kernel repository, I could measure the effect of these short-circuits when computing a fresh commit-graph file with changed-path Bloom filters using the command GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS=N time \ git commit-graph write --reachable --changed-paths and reporting the wall time and resulting commit-graph size. For Git, the results are | | N=1 | N=10 | N=512 | |--------|----------------|----------------|----------------| | HEAD~1 | 10.90s 9.18MB | 11.11s 9.34MB | 11.31s 9.35MB | | HEAD | 9.21s 8.62MB | 11.11s 9.29MB | 11.29s 9.34MB | For Linux, the results are | | N=1 | N=20 | N=512 | |--------|----------------|---------------|---------------| | HEAD~1 | 61.28s 64.3MB | 76.9s 72.6MB | 77.6s 72.6MB | | HEAD | 49.44s 56.3MB | 68.7s 65.9MB | 69.2s 65.9MB | Naturally, the improvement becomes much less as the limit grows, as fewer commits satisfy the short-circuit. Reported-by: SZEDER Gábor Signed-off-by: Derrick Stolee Signed-off-by: Taylor Blau --- bloom.c | 6 +++- diff.h | 2 -- t/t4216-log-bloom.sh | 85 +++++++++++++++++++++++++++++++++++++++----- tree-diff.c | 5 +-- 4 files changed, 82 insertions(+), 16 deletions(-) diff --git a/bloom.c b/bloom.c index 0cf1962dc5..ed54e96e57 100644 --- a/bloom.c +++ b/bloom.c @@ -222,7 +222,7 @@ struct bloom_filter *get_or_compute_bloom_filter(struct repository *r, diff_tree_oid(NULL, &c->object.oid, "", &diffopt); diffcore_std(&diffopt); - if (diffopt.num_changes <= settings->max_changed_paths) { + if (diff_queued_diff.nr <= settings->max_changed_paths) { struct hashmap pathmap; struct pathmap_hash_entry *e; struct hashmap_iter iter; @@ -259,6 +259,9 @@ struct bloom_filter *get_or_compute_bloom_filter(struct repository *r, diff_free_filepair(diff_queued_diff.queue[i]); } + if (hashmap_get_size(&pathmap) > settings->max_changed_paths) + goto cleanup; + filter->len = (hashmap_get_size(&pathmap) * settings->bits_per_entry + BITS_PER_WORD - 1) / BITS_PER_WORD; filter->data = xcalloc(filter->len, sizeof(unsigned char)); @@ -268,6 +271,7 @@ struct bloom_filter *get_or_compute_bloom_filter(struct repository *r, add_key_to_filter(&key, filter, settings); } + cleanup: hashmap_free_entries(&pathmap, struct pathmap_hash_entry, entry); } else { for (i = 0; i < diff_queued_diff.nr; i++) diff --git a/diff.h b/diff.h index e0c0af6286..1d32b71885 100644 --- a/diff.h +++ b/diff.h @@ -287,8 +287,6 @@ struct diff_options { /* If non-zero, then stop computing after this many changes. */ int max_changes; - /* For internal use only. */ - int num_changes; int ita_invisible_in_index; /* white-space error highlighting */ diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh index eb2bcc51f0..21b67677ef 100755 --- a/t/t4216-log-bloom.sh +++ b/t/t4216-log-bloom.sh @@ -177,20 +177,87 @@ test_expect_success 'persist filter settings' ' ' test_expect_success 'correctly report changes over limit' ' - git init 513changes && + git init limits && ( - cd 513changes && - for i in $(test_seq 1 513) + cd limits && + mkdir d && + mkdir d/e && + + for i in $(test_seq 1 2) do - echo $i >file$i.txt || return 1 + printf $i >d/file$i.txt && + printf $i >d/e/file$i.txt || return 1 done && - git add . && + + mkdir mode && + printf bash >mode/script.sh && + + mkdir foo && + touch foo/bar && + touch foo.txt && + + git add d foo foo.txt mode && git commit -m "files" && - git commit-graph write --reachable --changed-paths && - for i in $(test_seq 1 513) + + # Commit has 7 file and 4 directory adds + GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS=10 \ + GIT_TRACE2_EVENT="$(pwd)/trace" \ + git commit-graph write --reachable --changed-paths && + grep "\"max_changed_paths\":10" trace && + grep "\"filter_found_large\":1" trace && + + for path in $(git ls-tree -r --name-only HEAD) do - git -c core.commitGraph=false log -- file$i.txt >expect && - git log -- file$i.txt >actual && + git -c commitGraph.readChangedPaths=false log \ + -- $path >expect && + git log -- $path >actual && + test_cmp expect actual || return 1 + done && + + # Make a variety of path changes + printf new1 >d/e/file1.txt && + printf new2 >d/file2.txt && + rm d/e/file2.txt && + rm -r foo && + printf text >foo && + mkdir f && + printf new1 >f/file1.txt && + + # including a mode-only change (counts as modified) + git update-index --chmod=+x mode/script.sh && + + git add foo d f && + git commit -m "complicated" && + + # start from scratch and rebuild + rm -f .git/objects/info/commit-graph && + GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS=10 \ + GIT_TRACE2_EVENT="$(pwd)/trace-edit" \ + git commit-graph write --reachable --changed-paths && + grep "\"max_changed_paths\":10" trace-edit && + grep "\"filter_found_large\":2" trace-edit && + + for path in $(git ls-tree -r --name-only HEAD) + do + git -c commitGraph.readChangedPaths=false log \ + -- $path >expect && + git log -- $path >actual && + test_cmp expect actual || return 1 + done && + + # start from scratch and rebuild + rm -f .git/objects/info/commit-graph && + GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS=11 \ + GIT_TRACE2_EVENT="$(pwd)/trace-update" \ + git commit-graph write --reachable --changed-paths && + grep "\"max_changed_paths\":11" trace-update && + grep "\"filter_found_large\":0" trace-update && + + for path in $(git ls-tree -r --name-only HEAD) + do + git -c commitGraph.readChangedPaths=false log \ + -- $path >expect && + git log -- $path >actual && test_cmp expect actual || return 1 done ) diff --git a/tree-diff.c b/tree-diff.c index 6ebad1a46f..7cebbb327e 100644 --- a/tree-diff.c +++ b/tree-diff.c @@ -434,7 +434,7 @@ static struct combine_diff_path *ll_diff_tree_paths( if (diff_can_quit_early(opt)) break; - if (opt->max_changes && opt->num_changes > opt->max_changes) + if (opt->max_changes && diff_queued_diff.nr > opt->max_changes) break; if (opt->pathspec.nr) { @@ -521,7 +521,6 @@ static struct combine_diff_path *ll_diff_tree_paths( /* t↓ */ update_tree_entry(&t); - opt->num_changes++; } /* t > p[imin] */ @@ -539,7 +538,6 @@ static struct combine_diff_path *ll_diff_tree_paths( skip_emit_tp: /* ∀ pi=p[imin] pi↓ */ update_tp_entries(tp, nparent); - opt->num_changes++; } } @@ -557,7 +555,6 @@ struct combine_diff_path *diff_tree_paths( const struct object_id **parents_oid, int nparent, struct strbuf *base, struct diff_options *opt) { - opt->num_changes = 0; p = ll_diff_tree_paths(p, oid, parents_oid, nparent, base, opt); /*