Knowing your data structures does not mean being on the cutting edge of data structures research. It does mean knowing more than just vectors, lists, and hash

Knowing your data structures does not mean being on the cutting edge of data structures research. It does mean knowing more than just vectors, lists, and hash tables. It means choosing the right data structures for your problem -- something that can have profound effects on performance, much more so than the cache. Yes, people should know about the machine their code is running on, because when there are no asymptotic improvements to be made, constant factors start to matter. Right now, though, people tend to choose asymptotically suboptimal data structures and algorithms. Worrying about things like pipeline stalling when an algorithmic improvement is possible is basically the definition of premature optimization.