From fce87ae53883d22a9912abb2d11a926de747006e Mon Sep 17 00:00:00 2001 From: "Alexander N. Gavrilov" Date: Sat, 12 Jul 2008 22:00:57 +0400 Subject: [PATCH] Fix quadratic performance in rewrite_one. Parent commits are usually older than their children. Thus, on each iteration of the loop in rewrite_one, add_parents_to_list traverses all commits previously processed by the loop. It performs very poorly in case of very long rewrite chains. Signed-off-by: Alexander Gavrilov Signed-off-by: Junio C Hamano --- revision.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/revision.c b/revision.c index fc6675525..d464f14d5 100644 --- a/revision.c +++ b/revision.c @@ -412,10 +412,26 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit) commit->object.flags |= TREESAME; } -static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list) +static void insert_by_date_cached(struct commit *p, struct commit_list **head, + struct commit_list *cached_base, struct commit_list **cache) +{ + struct commit_list *new_entry; + + if (cached_base && p->date < cached_base->item->date) + new_entry = insert_by_date(p, &cached_base->next); + else + new_entry = insert_by_date(p, head); + + if (cache && (!*cache || p->date < (*cache)->item->date)) + *cache = new_entry; +} + +static int add_parents_to_list(struct rev_info *revs, struct commit *commit, + struct commit_list **list, struct commit_list **cache_ptr) { struct commit_list *parent = commit->parents; unsigned left_flag; + struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL; if (commit->object.flags & ADDED) return 0; @@ -445,7 +461,7 @@ static int add_parents_to_list(struct rev_info *revs, struct commit *commit, str if (p->object.flags & SEEN) continue; p->object.flags |= SEEN; - insert_by_date(p, list); + insert_by_date_cached(p, list, cached_base, cache_ptr); } return 0; } @@ -470,7 +486,7 @@ static int add_parents_to_list(struct rev_info *revs, struct commit *commit, str p->object.flags |= left_flag; if (!(p->object.flags & SEEN)) { p->object.flags |= SEEN; - insert_by_date(p, list); + insert_by_date_cached(p, list, cached_base, cache_ptr); } if(revs->first_parent_only) break; @@ -611,7 +627,7 @@ static int limit_list(struct rev_info *revs) if (revs->max_age != -1 && (commit->date < revs->max_age)) obj->flags |= UNINTERESTING; - if (add_parents_to_list(revs, commit, &list) < 0) + if (add_parents_to_list(revs, commit, &list, NULL) < 0) return -1; if (obj->flags & UNINTERESTING) { mark_parents_uninteresting(commit); @@ -1458,10 +1474,12 @@ enum rewrite_result { static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp) { + struct commit_list *cache = NULL; + for (;;) { struct commit *p = *pp; if (!revs->limited) - if (add_parents_to_list(revs, p, &revs->commits) < 0) + if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0) return rewrite_one_error; if (p->parents && p->parents->next) return rewrite_one_ok; @@ -1580,7 +1598,7 @@ static struct commit *get_revision_1(struct rev_info *revs) if (revs->max_age != -1 && (commit->date < revs->max_age)) continue; - if (add_parents_to_list(revs, commit, &revs->commits) < 0) + if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0) return NULL; } -- 2.30.2