revset: use parentsets.min in _children As stated in the comment, using the smartset 'min' will give more opportunity to be smart. It give a small but significant boost to the performance. Most of the time is still spend doing the actual computation but at least we can scrap some performance when it makes sense. revset #0: roots(0:tip) plain 0) 0.046600 1) 0.044109 94%