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rev-list: allow commit-only bitmap traversals

Ever since we added reachability bitmap support, we've been able to use it with rev-list to get the full list of objects, like: git rev-list --objects --use-bitmap-index --all But you can't do so without --objects, since we weren't ready to just show the commits. However, the internals of the bitmap code are mostly ready for this: they avoid opening up trees when walking to fill in the bitmaps. We just need to actually pass in the rev_info to traverse_bitmap_commit_list() so it knows which types to bother triggering our callback for. For completeness, the perf test now covers both the existing --objects case, as well as the new commits-only behavior (the objects one got way faster when we introduced bitmaps, but obviously isn't improved now). Here are numbers for linux.git: Test HEAD^ HEAD ------------------------------------------------------------------------ 5310.7: rev-list (commits) 8.29(8.10+0.19) 1.76(1.72+0.04) -78.8% 5310.8: rev-list (objects) 8.06(7.94+0.12) 8.14(7.94+0.13) +1.0% That run was cheating a little, as I didn't have any commit-graph in the repository, and we'd built it by default these days when running git-gc. Here are numbers with a commit-graph: Test HEAD^ HEAD ------------------------------------------------------------------------ 5310.7: rev-list (commits) 0.70(0.58+0.12) 0.51(0.46+0.04) -27.1% 5310.8: rev-list (objects) 6.20(6.09+0.10) 6.27(6.16+0.11) +1.1% Still an improvement, but a lot less impressive. We could have the perf script remove any commit-graph to show the out-sized effect, but it probably makes sense to leave it in what would be a more typical setup. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Feb 14, 2020 at 13:22 UTC 4eb707ebd681eb85306071db33ed70186d1642ac

7 files changed +34 -15

builtin/pack-objects.c

+2 -1

@@ -3054,7 +3054,8 @@ static int get_object_list_from_bitmap(struct rev_info *revs)

3054 display_progress(progress_state, nr_result);

3055 }

3056

3057 - traverse_bitmap_commit_list(bitmap_git, &add_object_entry_from_bitmap);

3057 + traverse_bitmap_commit_list(bitmap_git, revs,

3058 + &add_object_entry_from_bitmap);

3059 return 0;

3060 }

3061

builtin/rev-list.c

+1 -8

@@ -434,18 +434,11 @@ static int try_bitmap_traversal(struct rev_info *revs)

434 if (revs->max_count >= 0)

435 return -1;

436

437 - /*

438 - * Our bitmap result will return all objects, and we're not

439 - * yet prepared to show only particular types.

440 - */

441 - if (!revs->tag_objects || !revs->tree_objects || !revs->blob_objects)

442 - return -1;

443 -

437 bitmap_git = prepare_bitmap_walk(revs);

438 if (!bitmap_git)

439 return -1;

440

448 - traverse_bitmap_commit_list(bitmap_git, &show_object_fast);

441 + traverse_bitmap_commit_list(bitmap_git, revs, &show_object_fast);

442 free_bitmap_index(bitmap_git);

443 return 0;

444 }

pack-bitmap.c

+15 -5

@@ -599,6 +599,7 @@ static struct bitmap *find_objects(struct bitmap_index *bitmap_git,

599 }

600

601 static void show_extended_objects(struct bitmap_index *bitmap_git,

602 + struct rev_info *revs,

603 show_reachable_fn show_reach)

604 {

605 struct bitmap *objects = bitmap_git->result;

@@ -612,6 +613,11 @@ static void show_extended_objects(struct bitmap_index *bitmap_git,

613 continue;

614

615 obj = eindex->objects[i];

616 + if ((obj->type == OBJ_BLOB && !revs->blob_objects) ||

617 + (obj->type == OBJ_TREE && !revs->tree_objects) ||

618 + (obj->type == OBJ_TAG && !revs->tag_objects))

619 + continue;

620 +

621 show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);

622 }

623 }

@@ -872,16 +878,20 @@ int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,

878 }

879

880 void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,

881 + struct rev_info *revs,

882 show_reachable_fn show_reachable)

883 {

884 assert(bitmap_git->result);

885

886 show_objects_for_type(bitmap_git, OBJ_COMMIT, show_reachable);

880 - show_objects_for_type(bitmap_git, OBJ_TREE, show_reachable);

881 - show_objects_for_type(bitmap_git, OBJ_BLOB, show_reachable);

882 - show_objects_for_type(bitmap_git, OBJ_TAG, show_reachable);

883 -

884 - show_extended_objects(bitmap_git, show_reachable);

887 + if (revs->tree_objects)

888 + show_objects_for_type(bitmap_git, OBJ_TREE, show_reachable);

889 + if (revs->blob_objects)

890 + show_objects_for_type(bitmap_git, OBJ_BLOB, show_reachable);

891 + if (revs->tag_objects)

892 + show_objects_for_type(bitmap_git, OBJ_TAG, show_reachable);

893 +

894 + show_extended_objects(bitmap_git, revs, show_reachable);

895 }

896

897 static uint32_t count_object_type(struct bitmap_index *bitmap_git,

pack-bitmap.h

@@ -44,6 +44,7 @@ struct bitmap_index *prepare_bitmap_git(struct repository *r);

44 void count_bitmap_commit_list(struct bitmap_index *, uint32_t *commits,

45 uint32_t *trees, uint32_t *blobs, uint32_t *tags);

46 void traverse_bitmap_commit_list(struct bitmap_index *,

47 + struct rev_info *revs,

48 show_reachable_fn show_reachable);

49 void test_bitmap_walk(struct rev_info *revs);

50 struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs);

reachable.c

+1 -1

@@ -225,7 +225,7 @@ void mark_reachable_objects(struct rev_info *revs, int mark_reflog,

225

226 bitmap_git = prepare_bitmap_walk(revs);

227 if (bitmap_git) {

228 - traverse_bitmap_commit_list(bitmap_git, mark_object_seen);

228 + traverse_bitmap_commit_list(bitmap_git, revs, mark_object_seen);

229 free_bitmap_index(bitmap_git);

230 return;

231 }

t/perf/p5310-pack-bitmaps.sh

@@ -39,6 +39,14 @@ test_perf 'pack to file (bitmap)' '

39 git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null

40 '

42 +test_perf 'rev-list (commits)' '

43 + git rev-list --all --use-bitmap-index >/dev/null

44 +'

45 +

46 +test_perf 'rev-list (objects)' '

47 + git rev-list --all --use-bitmap-index --objects >/dev/null

48 +'

49 +

50 test_expect_success 'create partial bitmap state' '

51 # pick a commit to represent the repo tip in the past

52 cutoff=$(git rev-list HEAD~100 -1) &&

t/t5310-pack-bitmaps.sh

@@ -80,6 +80,12 @@ rev_list_tests() {

80 test_cmp expect actual

81 '

83 + test_expect_success "enumerate commits ($state)" '

84 + git rev-list --use-bitmap-index HEAD >actual &&

85 + git rev-list HEAD >expect &&

86 + test_bitmap_traversal --no-confirm-bitmaps expect actual

87 + '

88 +

89 test_expect_success "enumerate --objects ($state)" '

90 git rev-list --objects --use-bitmap-index HEAD >actual &&

91 git rev-list --objects HEAD >expect &&