Change revlog.heads to walk the revision graph using revision numbers On the kernel repo: $ hg heads -q before after RevlogNG 1.11 0.52 Revlogv0 0.80 0.69 Since the current code for tags has to find all the heads of the repo, this also helps there: $ hg tags before after RevlogNG 2.35 1.76 Revlogv0 2.04 1.90