| msg199402 - (view) |
Author: Eric Snow (eric.snow) *  |
Date: 2013-10-10 18:08 |
| There has been some discussion on python-dev about improving interpreter startup time. Christian Heimes brought up how the os module imports collections (so _Environ can inherit from it) [1], and mentioned a couple of solutions [2]. [1]https://mail.python.org/pipermail/python-dev/2013-October/129312.html [2]https://mail.python.org/pipermail/python-dev/2013-October/129367.html |
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| msg199404 - (view) |
Author: Eric Snow (eric.snow) * |
Date: 2013-10-10 18:35 |
| Here is a patch for an alternate approach. It does not require re-implementing MutableMapping (could get out of sync) and does not require rearranging collections.abc. Instead it uses a metaclass to resolve the import issue lazily. |
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| msg199405 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2013-10-10 18:39 |
| Nice trick :) |
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| msg199406 - (view) |
Author: Eric Snow (eric.snow) * |
Date: 2013-10-10 18:45 |
| And when the lazy base class gets resolved, the metaclass gets to say "You didn't see anything and I was never here." :) |
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| msg199449 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2013-10-11 09:11 |
| -1 on such hacks. I much prefer the _abcoll approach. |
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| msg199450 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2013-10-11 09:14 |
| The collections module is loaded by the io module. You removed "from collections.abc import MutableMapping" from os.py. To be useful, you have also to rewrite the whole io module to remove all references to the collections.abc module, right? |
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| msg199520 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2013-10-11 23:07 |
| The io module no longer imports collections.abc through the locale module. Eric, I'm with Antoine. Your patch is too much of a clever hack and uses tricks that are dark magic. _abcoll is much simpler and easier to understand. Plus it can be used from other modules, too. |
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| msg199521 - (view) |
Author: Eric Snow (eric.snow) * |
Date: 2013-10-11 23:17 |
| Not a problem. It is most definitely a hack. :) I put in up as an alternative to rearranging the collections module, but agree that doing so is preferable. I image that Raymond will make a decision on that one. |
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| msg199642 - (view) |
Author: Raymond Hettinger (rhettinger) * |
Date: 2013-10-12 23:35 |
| Christian, go ahead an rearrange the collections module. Move Lib/collections/abc.py to Lib/_collections_abc.py. Also, be sure to update source link on line 18 of Doc/library.collections.abc.rst |
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| msg199644 - (view) |
Author: Roundup Robot (python-dev)  |
Date: 2013-10-13 00:27 |
| New changeset 0b6052f2a8ee by Christian Heimes in branch 'default': Issue #19218: Rename collections.abc to _collections_abc in order to speed up interpreter start http://hg.python.org/cpython/rev/0b6052f2a8ee New changeset 7ea831581af4 by Christian Heimes in branch 'default': Issue #19218: Add facade collections.abc http://hg.python.org/cpython/rev/7ea831581af4 New changeset 62b6ecd1e463 by Christian Heimes in branch 'default': Issue #19218: set __name__ of _collections_abc to collections.abc in order to fix tests and keep beautiful qualified names. http://hg.python.org/cpython/rev/62b6ecd1e463 |
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| msg199647 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2013-10-13 00:53 |
| Thank you very much for your input and assistance! tip compared to v3.4.0a3: ### normal_startup ### Min: 0.506533 -> 0.313627: 1.62x faster Avg: 0.582504 -> 0.441796: 1.32x faster Significant (t=19.98) Stddev: 0.02397 -> 0.04366: 1.8213x larger |
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| msg199654 - (view) |
Author: Eric Snow (eric.snow) * |
Date: 2013-10-13 04:54 |
| Thanks, Christian. |
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| msg212282 - (view) |
Author: R. David Murray (r.david.murray) * |
Date: 2014-02-26 18:12 |
| For backward compatibility, shouldn't import _collections_abc in the __init__ file be import _collections_abc as abc ? |
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| msg212285 - (view) |
Author: R. David Murray (r.david.murray) * |
Date: 2014-02-26 18:26 |
| Opened issue 20784 to address the above. |
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