From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
The add_missing_tags() method currently has quadratic behavior.
This is due to a linear number (based on number of tags T) of
calls to in_merge_bases_many, which has linear performance (based
on number of commits C in the repository).
Replace this O(T * C) algorithm with an O(T + C) algorithm by
using get_reachable_subset(). We ignore the return list and focus
instead on the reachable_flag assigned to the commits we care
about, because we need to interact with the tag ref and not just
the commit object.
Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
remote.c | 34 +++++++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/remote.c b/remote.c
index 81f4f01b0..b850f2feb 100644
--- a/remote.c
+++ b/remote.c
@@ -1205,9 +1205,36 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
* sent to the other side.
*/
if (sent_tips.nr) {
+ const int reachable_flag = 1;
+ struct commit_list *found_commits;
+ struct commit **src_commits;
+ int nr_src_commits = 0, alloc_src_commits = 16;
+ ALLOC_ARRAY(src_commits, alloc_src_commits);
+
for_each_string_list_item(item, &src_tag) {
struct ref *ref = item->util;
+ struct commit *commit;
+
+ if (is_null_oid(&ref->new_oid))
+ continue;
+ commit = lookup_commit_reference_gently(the_repository,
+ &ref->new_oid,
+ 1);
+ if (!commit)
+ /* not pushing a commit, which is not an error */
+ continue;
+
+ ALLOC_GROW(src_commits, nr_src_commits + 1, alloc_src_commits);
+ src_commits[nr_src_commits++] = commit;
+ }
+
+ found_commits = get_reachable_subset(sent_tips.tip, sent_tips.nr,
+ src_commits, nr_src_commits,
+ reachable_flag);
+
+ for_each_string_list_item(item, &src_tag) {
struct ref *dst_ref;
+ struct ref *ref = item->util;
struct commit *commit;
if (is_null_oid(&ref->new_oid))
@@ -1223,7 +1250,7 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
* Is this tag, which they do not have, reachable from
* any of the commits we are sending?
*/
- if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
+ if (!(commit->object.flags & reachable_flag))
continue;
/* Add it in */
@@ -1231,7 +1258,12 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
oidcpy(&dst_ref->new_oid, &ref->new_oid);
dst_ref->peer_ref = copy_ref(ref);
}
+
+ clear_commit_marks_many(nr_src_commits, src_commits, reachable_flag);
+ free(src_commits);
+ free_commit_list(found_commits);
}
+
string_list_clear(&src_tag, 0);
free(sent_tips.tip);
}
--
gitgitgadget
