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Explain concrete (resource consumption) effects of PEP 393 a bit.

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Antoine Pitrou 2011-11-17 01:59:51 +01:00
parent d136aecd1f
commit beb7836260
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Doc/whatsnew/3.3.rst
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@ -84,11 +84,19 @@ Changes introduced by :pep:`393` are the following:
* non-BMP strings (``U+10000-U+10FFFF``) use 4 bytes per codepoint.
.. The memory usage of Python 3.3 is two to three times smaller than Python 3.2,
and a little bit better than Python 2.7, on a `Django benchmark
<http://mail.python.org/pipermail/python-dev/2011-September/113714.html>`_.
XXX The result should be moved in the PEP and a small summary about
performances and a link to the PEP should be added here.
The net effect is that for most applications, memory usage of string storage
should decrease significantly - especially compared to former wide unicode
builds - as, in many cases, strings will be pure ASCII even in international
contexts (because many strings store non-human language data, such as XML
fragments, HTTP headers, JSON-encoded data, etc.). We also hope that it
will, for the same reasons, increase CPU cache efficiency on non-trivial
applications.
.. The memory usage of Python 3.3 is two to three times smaller than Python 3.2,
and a little bit better than Python 2.7, on a `Django benchmark
<http://mail.python.org/pipermail/python-dev/2011-September/113714.html>`_.
XXX The result should be moved in the PEP and a link to the PEP should
be added here.
* With the death of narrow builds, the problems specific to narrow builds have
also been fixed, for example: