[Python-Dev] 2.4 news reaches interesting places

Jeremy Hylton jhylton at gmail.com
Thu Dec 9 20:56:41 CET 2004

On Thu, 9 Dec 2004 14:16:18 -0500, James Y Knight <foom at fuhm.net> wrote:
> On Dec 9, 2004, at 1:31 PM, Phillip J. Eby wrote:
> > Isn't it funny, by the way, that people don't go around talking about
> > how slow Jython is?  At least, I haven't seen it to the extent that
> > I've seen with CPython.
> People talk about how slow CPython is, is because they are writing code
> targeted for it that traditionally would have been written in C. Python
> *is* slower than C. You can try to deny it, but it is simple fact.
> However, python is a really nice language to program in. So people use
> it anyways. It is "fast enough" for many things.

I think you are exactly right.  It's easy to get the impression that
Python is slow when many programs written in Python *are* slowly than
the same program written in C, C++, or Java.  If you look are other
"dynamic" languages, you'll find that IronPython is often faster than
CPython and that Smalltalk and Common Lisp are often substantially
faster than Python.  Python isn't remarkably slow for a scripting
language, but it is not fast.

> There is currently a lot of work going on in the python community to
> make Python faster, which indicates both that Python is too slow for
> some people, and that it will be faster in the future. This is a good
> thing, and not something that should be shoved under the rug to try to
> pretend python is ultra mega super fast already.

I agree, although it's not clear to me how much faster it will be in
the future.  Making a *fast* Python based on our own virtual execution
environment (as opposed to piggybacking a JVM or CLR) is a big
project.  It's not clear than anyone has enough resources to make
credible effort, so we're left to piecemeal improvements.  The
improvement I see from 2.2 to 2.4 on my box is about 55% (measured
using pystone) over almost three years.

I think the right thing to do with PR is frame the question
differently.  We need to say that people use Python because it lets
them right clear, simple code or that it is easy to maintain or that
dynamic languages are excellent for prototyping -- whatever the
message is -- and simply avoid talking about speed.  There are a lot
of issues that affect the selection of a programming language, and
speed is not always the most important one.  It is easy for a
journalist to write about and it is easy to report (possibly
meaningless) measurements of speed.


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