Thank you for sharing this talk, was fun to watch. So the solution for all slow code is: use short usernames! 
Seriously now, I think what “Luke” does in the story, namely sample the same, non-randomized setup repeatedly can still tell you something: how good your measurement method is (reproducibility). It made me think about the post over here, the no-op benchmark. If you sample the same thing over and over again, and get results all over the place (large standard deviation), your precision is simply bad. That then makes it harder to compare different sets of samples, even if you made sure that you’re not sampling distinct populations (comparing apples with pears).