From: "Garima Singh via GitGitGadget" <gitgitgadget@gmail.com> To: git@vger.kernel.org Cc: stolee@gmail.com, szeder.dev@gmail.com, jonathantanmy@google.com, Garima Singh <garima.singh@microsoft.com>, Garima Singh <garima.singh@microsoft.com> Subject: [PATCH v4 12/15] revision.c: use Bloom filters to speed up path based revision walks Date: Mon, 06 Apr 2020 16:59:52 +0000 [thread overview] Message-ID: <617f549ef259424658a84dd67a98685328f6b850.1586192395.git.gitgitgadget@gmail.com> (raw) In-Reply-To: <pull.497.v4.git.1586192395.gitgitgadget@gmail.com> From: Garima Singh <garima.singh@microsoft.com> Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> --- bloom.c | 20 +++++++++++++ bloom.h | 4 +++ revision.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- revision.h | 11 +++++++ 4 files changed, 118 insertions(+), 2 deletions(-) diff --git a/bloom.c b/bloom.c index 0f714dd76ae..c5b461d1cfe 100644 --- a/bloom.c +++ b/bloom.c @@ -253,3 +253,23 @@ struct bloom_filter *get_bloom_filter(struct repository *r, return filter; } + +int bloom_filter_contains(const struct bloom_filter *filter, + const struct bloom_key *key, + const struct bloom_filter_settings *settings) +{ + int i; + uint64_t mod = filter->len * BITS_PER_WORD; + + if (!mod) + return -1; + + for (i = 0; i < settings->num_hashes; i++) { + uint64_t hash_mod = key->hashes[i] % mod; + uint64_t block_pos = hash_mod / BITS_PER_WORD; + if (!(filter->data[block_pos] & get_bitmask(hash_mod))) + return 0; + } + + return 1; +} \ No newline at end of file diff --git a/bloom.h b/bloom.h index 760d7122374..b935186425d 100644 --- a/bloom.h +++ b/bloom.h @@ -83,4 +83,8 @@ struct bloom_filter *get_bloom_filter(struct repository *r, struct commit *c, int compute_if_not_present); +int bloom_filter_contains(const struct bloom_filter *filter, + const struct bloom_key *key, + const struct bloom_filter_settings *settings); + #endif \ No newline at end of file diff --git a/revision.c b/revision.c index 8136929e236..d3fcb7c6ff6 100644 --- a/revision.c +++ b/revision.c @@ -29,6 +29,7 @@ #include "prio-queue.h" #include "hashmap.h" #include "utf8.h" +#include "bloom.h" volatile show_early_output_fn_t show_early_output; @@ -624,11 +625,80 @@ static void file_change(struct diff_options *options, options->flags.has_changes = 1; } +static void prepare_to_use_bloom_filter(struct rev_info *revs) +{ + struct pathspec_item *pi; + char *path_alloc = NULL; + const char *path; + int last_index; + int len; + + if (!revs->commits) + return; + + repo_parse_commit(revs->repo, revs->commits->item); + + if (!revs->repo->objects->commit_graph) + return; + + revs->bloom_filter_settings = revs->repo->objects->commit_graph->bloom_filter_settings; + if (!revs->bloom_filter_settings) + return; + + pi = &revs->pruning.pathspec.items[0]; + last_index = pi->len - 1; + + /* remove single trailing slash from path, if needed */ + if (pi->match[last_index] == '/') { + path_alloc = xstrdup(pi->match); + path_alloc[last_index] = '\0'; + path = path_alloc; + } else + path = pi->match; + + len = strlen(path); + + revs->bloom_key = xmalloc(sizeof(struct bloom_key)); + fill_bloom_key(path, len, revs->bloom_key, revs->bloom_filter_settings); + + free(path_alloc); +} + +static int check_maybe_different_in_bloom_filter(struct rev_info *revs, + struct commit *commit) +{ + struct bloom_filter *filter; + int result; + + if (!revs->repo->objects->commit_graph) + return -1; + + if (commit->generation == GENERATION_NUMBER_INFINITY) + return -1; + + filter = get_bloom_filter(revs->repo, commit, 0); + + if (!filter) { + return -1; + } + + if (!filter->len) { + return -1; + } + + result = bloom_filter_contains(filter, + revs->bloom_key, + revs->bloom_filter_settings); + + return result; +} + static int rev_compare_tree(struct rev_info *revs, - struct commit *parent, struct commit *commit) + struct commit *parent, struct commit *commit, int nth_parent) { struct tree *t1 = get_commit_tree(parent); struct tree *t2 = get_commit_tree(commit); + int bloom_ret = 1; if (!t1) return REV_TREE_NEW; @@ -653,11 +723,19 @@ static int rev_compare_tree(struct rev_info *revs, return REV_TREE_SAME; } + if (revs->bloom_key && !nth_parent) { + bloom_ret = check_maybe_different_in_bloom_filter(revs, commit); + + if (bloom_ret == 0) + return REV_TREE_SAME; + } + tree_difference = REV_TREE_SAME; revs->pruning.flags.has_changes = 0; if (diff_tree_oid(&t1->object.oid, &t2->object.oid, "", &revs->pruning) < 0) return REV_TREE_DIFFERENT; + return tree_difference; } @@ -855,7 +933,7 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit) die("cannot simplify commit %s (because of %s)", oid_to_hex(&commit->object.oid), oid_to_hex(&p->object.oid)); - switch (rev_compare_tree(revs, p, commit)) { + switch (rev_compare_tree(revs, p, commit, nth_parent)) { case REV_TREE_SAME: if (!revs->simplify_history || !relevant_commit(p)) { /* Even if a merge with an uninteresting @@ -3362,6 +3440,8 @@ int prepare_revision_walk(struct rev_info *revs) FOR_EACH_OBJECT_PROMISOR_ONLY); } + if (revs->pruning.pathspec.nr == 1 && !revs->reflog_info) + prepare_to_use_bloom_filter(revs); if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED) commit_list_sort_by_date(&revs->commits); if (revs->no_walk) @@ -3379,6 +3459,7 @@ int prepare_revision_walk(struct rev_info *revs) simplify_merges(revs); if (revs->children.name) set_children(revs); + return 0; } diff --git a/revision.h b/revision.h index 475f048fb61..7c026fe41fc 100644 --- a/revision.h +++ b/revision.h @@ -56,6 +56,8 @@ struct repository; struct rev_info; struct string_list; struct saved_parents; +struct bloom_key; +struct bloom_filter_settings; define_shared_commit_slab(revision_sources, char *); struct rev_cmdline_info { @@ -291,6 +293,15 @@ struct rev_info { struct revision_sources *sources; struct topo_walk_info *topo_walk_info; + + /* Commit graph bloom filter fields */ + /* The bloom filter key for the pathspec */ + struct bloom_key *bloom_key; + /* + * The bloom filter settings used to generate the key. + * This is loaded from the commit-graph being used. + */ + struct bloom_filter_settings *bloom_filter_settings; }; int ref_excluded(struct string_list *, const char *path); -- gitgitgadget
next prev parent reply other threads:[~2020-04-06 17:00 UTC|newest] Thread overview: 159+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-12-20 22:05 [PATCH 0/9] [RFC] Changed Paths Bloom Filters Garima Singh via GitGitGadget 2019-12-20 22:05 ` [PATCH 1/9] commit-graph: add --changed-paths option to write Garima Singh via GitGitGadget 2020-01-01 20:20 ` Jakub Narebski 2019-12-20 22:05 ` [PATCH 2/9] commit-graph: write changed paths bloom filters Garima Singh via GitGitGadget 2019-12-21 16:48 ` Philip Oakley 2020-01-06 18:44 ` Jakub Narebski 2020-01-13 19:48 ` Garima Singh 2019-12-20 22:05 ` [PATCH 3/9] commit-graph: use MAX_NUM_CHUNKS Garima Singh via GitGitGadget 2020-01-07 12:19 ` Jakub Narebski 2019-12-20 22:05 ` [PATCH 4/9] commit-graph: document bloom filter format Garima Singh via GitGitGadget 2020-01-07 14:46 ` Jakub Narebski 2019-12-20 22:05 ` [PATCH 5/9] commit-graph: write changed path bloom filters to commit-graph file Garima Singh via GitGitGadget 2020-01-07 16:01 ` Jakub Narebski 2020-01-14 15:14 ` Garima Singh 2019-12-20 22:05 ` [PATCH 6/9] commit-graph: test commit-graph write --changed-paths Garima Singh via GitGitGadget 2020-01-08 0:32 ` Jakub Narebski 2019-12-20 22:05 ` [PATCH 7/9] commit-graph: reuse existing bloom filters during write Garima Singh via GitGitGadget 2020-01-09 19:12 ` Jakub Narebski 2019-12-20 22:05 ` [PATCH 8/9] revision.c: use bloom filters to speed up path based revision walks Garima Singh via GitGitGadget 2020-01-11 0:27 ` Jakub Narebski 2020-01-15 0:08 ` Garima Singh 2019-12-20 22:05 ` [PATCH 9/9] commit-graph: add GIT_TEST_COMMIT_GRAPH_BLOOM_FILTERS test flag Garima Singh via GitGitGadget 2020-01-11 19:56 ` Jakub Narebski 2020-01-15 0:55 ` Garima Singh 2019-12-20 22:14 ` [PATCH 0/9] [RFC] Changed Paths Bloom Filters Junio C Hamano 2019-12-22 9:26 ` Christian Couder 2019-12-22 9:38 ` Jeff King 2020-01-01 12:04 ` Jakub Narebski 2019-12-22 9:30 ` Jeff King 2019-12-22 9:32 ` [PATCH 1/3] commit-graph: examine changed-path objects in pack order Jeff King 2019-12-27 14:51 ` Derrick Stolee 2019-12-29 6:12 ` Jeff King 2019-12-29 6:28 ` Jeff King 2019-12-30 14:37 ` Derrick Stolee 2019-12-30 14:51 ` Derrick Stolee 2019-12-22 9:32 ` [PATCH 2/3] commit-graph: free large diffs, too Jeff King 2019-12-27 14:52 ` Derrick Stolee 2019-12-22 9:32 ` [PATCH 3/3] commit-graph: stop using full rev_info for diffs Jeff King 2019-12-27 14:53 ` Derrick Stolee 2019-12-26 14:21 ` [PATCH 0/9] [RFC] Changed Paths Bloom Filters Derrick Stolee 2019-12-29 6:03 ` Jeff King 2019-12-27 16:11 ` Derrick Stolee 2019-12-29 6:24 ` Jeff King 2019-12-30 16:04 ` Derrick Stolee 2019-12-30 17:02 ` Junio C Hamano 2019-12-31 16:45 ` Jakub Narebski 2020-01-13 16:54 ` Garima Singh 2020-01-20 13:48 ` Jakub Narebski 2020-01-21 16:14 ` Garima Singh 2020-02-02 18:43 ` Jakub Narebski 2020-01-21 23:40 ` Emily Shaffer 2020-01-27 18:24 ` Garima Singh 2020-02-01 23:32 ` Jakub Narebski 2020-02-05 22:56 ` [PATCH v2 00/11] " Garima Singh via GitGitGadget 2020-02-05 22:56 ` [PATCH v2 01/11] commit-graph: use MAX_NUM_CHUNKS Garima Singh via GitGitGadget 2020-02-09 12:39 ` Jakub Narebski 2020-02-05 22:56 ` [PATCH v2 02/11] bloom: core Bloom filter implementation for changed paths Garima Singh via GitGitGadget 2020-02-15 17:17 ` Jakub Narebski 2020-02-16 16:49 ` Jakub Narebski 2020-02-22 0:32 ` Garima Singh 2020-02-23 13:38 ` Jakub Narebski 2020-02-24 17:34 ` Garima Singh 2020-02-24 18:20 ` Jakub Narebski 2020-02-05 22:56 ` [PATCH v2 03/11] diff: halt tree-diff early after max_changes Derrick Stolee via GitGitGadget 2020-02-17 0:00 ` Jakub Narebski 2020-02-22 0:37 ` Garima Singh 2020-02-05 22:56 ` [PATCH v2 04/11] commit-graph: compute Bloom filters for changed paths Garima Singh via GitGitGadget 2020-02-17 21:56 ` Jakub Narebski 2020-02-22 0:55 ` Garima Singh 2020-02-23 17:34 ` Jakub Narebski 2020-02-05 22:56 ` [PATCH v2 05/11] commit-graph: examine changed-path objects in pack order Jeff King via GitGitGadget 2020-02-18 17:59 ` Jakub Narebski 2020-02-24 18:29 ` Garima Singh 2020-02-05 22:56 ` [PATCH v2 06/11] commit-graph: examine commits by generation number Derrick Stolee via GitGitGadget 2020-02-19 0:32 ` Jakub Narebski 2020-02-24 20:45 ` Garima Singh 2020-02-05 22:56 ` [PATCH v2 07/11] commit-graph: write Bloom filters to commit graph file Garima Singh via GitGitGadget 2020-02-19 15:13 ` Jakub Narebski 2020-02-24 21:14 ` Garima Singh 2020-02-25 11:40 ` Jakub Narebski 2020-02-25 15:58 ` Garima Singh 2020-02-05 22:56 ` [PATCH v2 08/11] commit-graph: reuse existing Bloom filters during write Garima Singh via GitGitGadget 2020-02-20 18:48 ` Jakub Narebski 2020-02-24 21:45 ` Garima Singh 2020-02-05 22:56 ` [PATCH v2 09/11] commit-graph: add --changed-paths option to write subcommand Garima Singh via GitGitGadget 2020-02-20 20:28 ` Jakub Narebski 2020-02-24 21:51 ` Garima Singh 2020-02-25 12:10 ` Jakub Narebski 2020-02-20 22:10 ` Bryan Turner 2020-02-22 1:44 ` Garima Singh 2020-02-05 22:56 ` [PATCH v2 10/11] revision.c: use Bloom filters to speed up path based revision walks Garima Singh via GitGitGadget 2020-02-21 17:31 ` Jakub Narebski 2020-02-21 22:45 ` Jakub Narebski 2020-02-05 22:56 ` [PATCH v2 11/11] commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag Garima Singh via GitGitGadget 2020-02-22 0:11 ` Jakub Narebski 2020-02-07 13:52 ` [PATCH v2 00/11] Changed Paths Bloom Filters SZEDER Gábor 2020-02-07 15:09 ` Garima Singh 2020-02-07 15:36 ` Derrick Stolee 2020-02-07 16:15 ` SZEDER Gábor 2020-02-07 16:33 ` Derrick Stolee 2020-02-11 19:08 ` Garima Singh 2020-02-08 23:04 ` Jakub Narebski 2020-02-21 17:41 ` Garima Singh 2020-03-29 18:36 ` Junio C Hamano 2020-03-30 0:31 ` [PATCH v3 00/16] " Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 01/16] commit-graph: define and use MAX_NUM_CHUNKS Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 02/16] bloom.c: add the murmur3 hash implementation Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 03/16] bloom.c: introduce core Bloom filter constructs Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 04/16] bloom.c: core Bloom filter implementation for changed paths Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 05/16] diff: halt tree-diff early after max_changes Derrick Stolee via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 06/16] commit-graph: compute Bloom filters for changed paths Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 07/16] commit-graph: examine changed-path objects in pack order Jeff King via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 08/16] commit-graph: examine commits by generation number Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 09/16] diff: skip batch object download when possible Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 10/16] commit-graph: write Bloom filters to commit graph file Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 11/16] commit-graph: reuse existing Bloom filters during write Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 12/16] commit-graph: add --changed-paths option to write subcommand Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 13/16] revision.c: use Bloom filters to speed up path based revision walks Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 14/16] revision.c: add trace2 stats around Bloom filter usage Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 15/16] t4216: add end to end tests for git log with Bloom filters Garima Singh via GitGitGadget 2020-03-30 0:31 ` [PATCH v3 16/16] commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 00/15] Changed Paths Bloom Filters Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 01/15] commit-graph: define and use MAX_NUM_CHUNKS Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 02/15] bloom.c: add the murmur3 hash implementation Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 03/15] bloom.c: introduce core Bloom filter constructs Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 04/15] bloom.c: core Bloom filter implementation for changed paths Garima Singh via GitGitGadget 2020-06-27 15:53 ` SZEDER Gábor 2020-04-06 16:59 ` [PATCH v4 05/15] diff: halt tree-diff early after max_changes Derrick Stolee via GitGitGadget 2020-08-04 14:47 ` SZEDER Gábor 2020-08-04 16:25 ` Derrick Stolee 2020-08-04 17:00 ` SZEDER Gábor 2020-08-04 17:31 ` Derrick Stolee 2020-08-05 17:08 ` Derrick Stolee 2020-04-06 16:59 ` [PATCH v4 06/15] commit-graph: compute Bloom filters for changed paths Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 07/15] commit-graph: examine changed-path objects in pack order Jeff King via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 08/15] commit-graph: examine commits by generation number Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 09/15] commit-graph: write Bloom filters to commit graph file Garima Singh via GitGitGadget 2020-05-29 8:57 ` SZEDER Gábor 2020-05-29 13:35 ` Derrick Stolee 2020-05-31 17:23 ` SZEDER Gábor 2020-07-09 17:00 ` [PATCH] commit-graph: fix "Writing out commit graph" progress counter SZEDER Gábor 2020-07-09 18:01 ` Derrick Stolee 2020-07-09 18:20 ` Derrick Stolee 2020-04-06 16:59 ` [PATCH v4 10/15] commit-graph: reuse existing Bloom filters during write Garima Singh via GitGitGadget 2020-06-19 14:02 ` SZEDER Gábor 2020-06-19 19:28 ` Junio C Hamano 2020-07-27 21:33 ` SZEDER Gábor 2020-04-06 16:59 ` [PATCH v4 11/15] commit-graph: add --changed-paths option to write subcommand Garima Singh via GitGitGadget 2020-06-07 22:21 ` SZEDER Gábor 2020-04-06 16:59 ` Garima Singh via GitGitGadget [this message] 2020-06-26 6:34 ` [PATCH v4 12/15] revision.c: use Bloom filters to speed up path based revision walks SZEDER Gábor 2020-04-06 16:59 ` [PATCH v4 13/15] revision.c: add trace2 stats around Bloom filter usage Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 14/15] t4216: add end to end tests for git log with Bloom filters Garima Singh via GitGitGadget 2020-04-06 16:59 ` [PATCH v4 15/15] commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag Garima Singh via GitGitGadget 2020-04-08 15:51 ` [PATCH v4 00/15] Changed Paths Bloom Filters Derrick Stolee 2020-04-08 19:21 ` Junio C Hamano 2020-04-08 20:05 ` Jakub Narębski 2020-04-12 20:34 ` Taylor Blau 2020-03-05 19:49 ` [PATCH 0/9] [RFC] " Garima Singh
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