[Python-Dev] importlib quest (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Mon Feb 6 21:44:48 CET 2012

On Mon, 6 Feb 2012 20:49:48 +0100 Antoine Pitrou <solipsis at pitrou.net> wrote:

On Mon, 6 Feb 2012 09:57:56 -0500 Brett Cannon <brett at python.org> wrote: > Thanks for any help people can provide me on this now 5 year quest to get > this work finished.

Do you have any plan to solve the performance issue? _$ ./python -m timeit -s "import sys; mod='struct'" _ "import(mod); del sys.modules[mod]" 10000 loops, best of 3: 75.3 usec per loop _$ ./python -m timeit -s "import sys; mod='struct'; from importlib import import" _ "import(mod); del sys.modules[mod]" 1000 loops, best of 3: 421 usec per loop

The culprit for the overhead is likely to be PathFinder.find_module:

$ ./python -m timeit -s "import sys; mod='struct'; from importlib._bootstrap import _DefaultPathFinder; finder=_DefaultPathFinder" "finder.find_module('struct')" 1000 loops, best of 3: 355 usec per loop $ ./python -S -m timeit -s "import sys; mod='struct'; from importlib._bootstrap import _DefaultPathFinder; finder=_DefaultPathFinder" "finder.find_module('struct')" 10000 loops, best of 3: 176 usec per loop

Note how it's dependent on sys.path length. On an installed Python with many additional sys.path entries (e.g. because of distribute-based module installs), import times will be much worse.

Regards

Antoine.

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