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gh-121423: Improve import time of
socket
by writingsocket.errorTab
as a constant and lazy import modules #121424gh-121423: Improve import time of
socket
by writingsocket.errorTab
as a constant and lazy import modules #121424Changes from 4 commits
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I suggest to use a global variable to avoid the import at each call:
You can define the selectors variable to None at the top of the file with a comment:
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I checked several recent PRs making module loading lazy, but most of them do not use the pattern with a global variable (I suspect for readability reasons).
@vstinner Are there any other reasons besides the small performance improvement for using the global variable?
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@serhiy-storchaka: Do you think that it's still useful in 2024 to use a global variable to avoid
import selectors
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I'd just do the import. It's a mere dict lookup without a conditional when the import has already happened.
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Just measure. It is more than a mere dict lookup (we also need to check that the module is not partially initialized, this adds 2 more dict lookups or like).
In this case, I think that the difference may be small even in comparison with a single os.fstat() call. The idiom proposed by @vstinner may be used when the whole function is very fast.
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Please rename to
Misc/NEWS.d/next/Library/2024-07-06-12-37-10.gh-issue-118761.vnxrl4.rst
(containinggh-issue-118761
) and we're ready to merge :)There was a problem hiding this comment.
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#121423 is the right issue.