make baseline: 1.8: real 3m41.714s user 6m52.414s sys 0m36.662s
2.2: real 6m8.344s user 12m51.799s sys 0m34.875s I think this warrants some deeper look, though: I have the impression that the lilypond-book regression tests aren't parallelized. They also suffer from the higher start up costs (there are some 60 of them, so that's 90 seconds right there). https://codereview.appspot.com/569390043/
