[Python-Dev] 2.3 startup speed? (original) (raw)

Jeremy Hylton jeremy@zope.com
11 Jul 2003 10:27:23 -0400

On Fri, 2003-07-11 at 10:16, Fred L. Drake, Jr. wrote:

Perhaps, but... those imports only happen if it already looks like you're running from a build directory, so they don't impact the imports for an installed Python.

You are so true. I just did fresh installs of 2.2.3 and 2.3 to see what happens when I run from an install Python.

A nice minimal set of imports for 2.2.3:

import site import os import posix import posixpath import stat import UserDict import copy_reg import types import future

There are a lot more for 2.3 (and each one costs more).

import zipimport import site import os import posix import posixpath import stat import UserDict import copy_reg import types import warnings import linecache import re import sre import sre_compile import _sre import sre_constants import sre_parse import string import encodings import codecs import _codecs import encodings.aliases import encodings.iso8859_15

We can blame the extra imports on three new features.

The zip import feature requires the zipimport module.

The warnings feature requires warnings, linecache, and re, where re is costly -- seven imports in total. The top-level "import re" was removed from warnings.py, but it doesn't make any difference. The routine that uses the re module is called from the top-level of the warnings module.

The default file system encoding feature requires the encodings and codecs packages to be loaded. That's another five imports.

Anyone want to drop warnings and encodings? <0.9 wink>

Jeremy