python simply not scaleable enough for google?

Robert Brown bbrown at
Sat Nov 14 23:56:39 CET 2009

Vincent Manis <vmanis at> writes:
> The false statement you made is that `... Python *the language* is specified
> in a way that makes executing Python programs quickly very very difficult.
> I refuted it by citing several systems that implement languages with
> semantics similar to those of Python, and do so efficiently.

The semantic details matter.  Please read Willem's reply to your post.  It
contains a long list of specific differences between Python (CPython) language
semantics and Common Lisp language semantics that cause Python performance to

> OK, let me try this again. My assertion is that with some combination of
> JITting, reorganization of the Python runtime, and optional static
> declarations, Python can be made acceptably fast, which I define as program
> runtimes on the same order of magnitude as those of the same programs in C
> (Java and other languages have established a similar goal). I am not pushing
> optional declarations, as it's worth seeing what we can get out of
> JITting. If you wish to refute this assertion, citing behavior in CPython or
> another implementation is not enough. You have to show that the stated
> feature *cannot* be made to run in an acceptable time.

It's hard to refute your assertion.  You're claiming that some future
hypothetical Python implementation will have excellent performance via a JIT.
On top of that you say that you're willing to change the definition of the
Python language, say by adding type declarations, if an implementation with a
JIT doesn't pan out.  If you change the Python language to address the
semantic problems Willem lists in his post and also add optional type
declarations, then Python becomes closer to Common Lisp, which we know can be
executed efficiently, within the same ballpark as C and Java.


More information about the Python-list mailing list