> Remember, though, that
> when run as a single instance, at least in the existing engine, the re
> compiler caches recent compiles, so repeatedly compiling an expression
> flattens the overhead in a single run to a single compile and lookup,
> where as your tests recompile at each test

They don't. The pattern is compiled only once. Please take a look at
http://docs.python.org/library/timeit.html#command-line-interface