string-list: use ALLOC_GROW macro when reallocing string_list

Use ALLOC_GROW() macro when reallocing a string_list array rather than simply increasing it by 32. This is a performance optimization. During status on a very large repo and there are many changes, a significant percentage of the total run time was spent reallocing the wt_status.changes array. This change decreased the time in wt_status_collect_changes_worktree() from 125 seconds to 45 seconds on my very large repository. Signed-off-by: Jeff Hostetler <[email protected]>
git-for-windows · Apr 2, 2017 · 497dfed · 497dfed
1 parent 5eebf65
commit 497dfed
Showing 1 changed file with 2 additions and 4 deletions.
diff --git a/string-list.c b/string-list.c
@@ -41,10 +41,8 @@ static int add_entry(int insert_at, struct string_list *list, const char *string
 	if (exact_match)
 		return -1 - index;
 
-	if (list->nr + 1 >= list->alloc) {
-		list->alloc += 32;
-		REALLOC_ARRAY(list->items, list->alloc);
-	}
+	if (list->nr + 1 >= list->alloc)
+		ALLOC_GROW(list->items, list->nr+1, list->alloc);
 	if (index < list->nr)
 		memmove(list->items + index + 1, list->items + index,
 				(list->nr - index)