Hi Herbert, Thanks for the careful performance experiment! Can you please put all the details into the issue tracker so they don't get lost? We have a couple of performance issues open, and we know that there are performance bugs in Hadrian leading to too sequential build (a recent example is #464), but we haven't had time to optimise Hadrian yet. In any case it's good to know where we stand right now. I hope you'll be willing to repeat your experiment once these bugs are fixed. Cheers, Andrey