pickle and module package
M.-A. Lemburg
mal at lemburg.com
Tue May 18 15:07:44 EDT 1999
Fred L. Drake wrote:
>
> M.-A. Lemburg writes:
> > I'd say, there's no way for the import logic to tell whether
> > you are about to import the same module a second time... unless
> > maybe, if it scans the sys.modules dict for filenames of the modules
> > and then checks for identical files. But that would reduce import
> > performance dramatically and not be worth it.
>
> A dictionary could be used that maps filenames to modules; this can
> simply be checked and updated during the slow path through import.
> This shouldn't be much slower than it already is. ;-)
> The filesnames would have to be absolute for it to work; there's
> currently nothing that does this for pathnames in the core
> interpreter. I'd be quite happy if __file__ could be relied on to be
> absolute as well!
Hmm, so maybe there's a chance after all... a dictionary lookup
would certainly not effect the import performance in any
noticable way.
That would also provide a chance to get that fastpath hook into
the mechanism to eliminate at least a few of the stat() calls
done at startup.
Just wish I had some time to look into this a bit further...
if anyone wants to try, here is the fastpath stuff I've
written some time ago:
http://starship.skyport.net/~lemburg/fastpath.zip
--
Marc-Andre Lemburg
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