I'd go further and focus on "small efficiencies" part of that. The assumption used to be high that you would stay cognizant of large efficiencies. In a very r

I'd go further and focus on "small efficiencies" part of that. The assumption used to be high that you would stay cognizant of large efficiencies. In a very real sense, this is like a lot of the rhetoric around Big O analysis. From all that you ever hear online, you would think that Knuth's analysis was focused on only the Big O descriptions of algorithms. Reading the book, however, you find much more detailed takes of individual algorithms. Such that the aim was never to not be able to do the small, but realize that the comparison is dominated by the big. Such is it with efficiency. The assumption was that you did not pick purposely inefficient methods, at large. And that you can focus on the very small level details where you get the best return on them. Now, I think "clean code" is getting a bit thrown under here. Picking the specific examples that were easy to talk about in a pedagogical manner is not doing any favors to the general ideas from either side. And I consider myself mostly on the anti side of the "clean code" debate.