On Sat, 04 Aug 2012 18:38:33 -0700, Paul Rubin wrote: > Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> writes: >> Runtime optimizations that target the common case, but fall back to >> unoptimized code in the rare cases that the optimization doesn't apply, >> offer the opportunity of big speedups for most code at the cost of >> trivial slowdowns when you do something unusual. > > The problem is you can't always tell if the unusual case is being > exercised without an expensive dynamic check, which in some cases must > be repeated in every iteration of a critical inner loop, even though it > turns out that the program never actually uses the unusual case.
I never said optimizing Python was easy :) Obviously if the check is expensive enough, the optimization isn't going to be worth doing. But often the check is not so expensive, or is just a matter of tedious and careful book-keeping. I don't wish to dispute that optimizing Python is hard, but it's not a Hard Problem like factorizing huge integers, or solving the Palestine/ Israeli conflict. It's hard like cleaning your house after a gang of drunken frat boys have partied all weekend. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
