> Is it concerning that most Haskell optimization guides talk about adding ! to enforce evaluation?
No, it's not. It's a perfectly reasonable consequence of Haskell's design choices.
> What I want to say is that you really have to know a lot about Haskell to predict a program's runtime performance
And you really have to know a lot about CPUs to predict cache locality issues in C/C++ programs. This is to be expected.
Austin Seipp, one of the core contributors to GHC, has a really good writeup about this in the comments over at the haskell subreddit for this same article.
No, it's not. It's a perfectly reasonable consequence of Haskell's design choices.
> What I want to say is that you really have to know a lot about Haskell to predict a program's runtime performance
And you really have to know a lot about CPUs to predict cache locality issues in C/C++ programs. This is to be expected.
Austin Seipp, one of the core contributors to GHC, has a really good writeup about this in the comments over at the haskell subreddit for this same article.
http://www.reddit.com/r/haskell/comments/2jbl78/from_60_fram...