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GeezerVison is showing github.com — bpo-37348: optimize decoding ASCII string by methane · Pull Request #14283 · python/cpython

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@methane

@methane methane commented Jun 21, 2019 •
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Use _PyUnicode_Writer only after ascii_decode is failed.

https://bugs.python.org/issue37348

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methane added 2 commits June 21, 2019 19:08
@methane
Skip using _PyUnicodeWriter for simple ASCII string
dcd2219
@methane
code cleanup
40750a2
@the-knights-who-say-ni the-knights-who-say-ni added the CLA signed label Jun 21, 2019
@bedevere-bot bedevere-bot added the awaiting core review label Jun 21, 2019
@methane
fix error handler writes after allocated
60be283
@methane methane mentioned this pull request Jun 21, 2019
bpo-37348: optimize decoding ASCII string #14291
Closed
@brettcannon brettcannon added the performance Performance or resource usage label Jun 21, 2019
vstinner
vstinner reviewed Jun 21, 2019
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Comment thread Objects/unicodeobject.c Resolved

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methane added 3 commits June 23, 2019 00:11
@methane
add _PyUnicodeWriter_InitWithBuffer function
0c5d9d4
@methane
fix indent
3d34e17
@methane
fix return type
7f5698d
@methane

methane commented Jun 22, 2019

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$ ./python -m pyperf timeit --compare-to=./python-master -s 'b=b"foo"' -- 'b.decode()'
python-master: ..................... 83.3 ns +- 1.2 ns
python: ..................... 72.4 ns +- 1.1 ns

Mean +- std dev: [python-master] 83.3 ns +- 1.2 ns -> [python] 72.4 ns +- 1.1 ns: 1.15x faster (-13%)

PyUnicode_FromString("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");: about 38ns -> 28ns
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@methane
add NEWS entry
24c7b2a
@methane
methane merged commit 770847a into python:master Jun 24, 2019
@bedevere-bot bedevere-bot removed the awaiting core review label Jun 24, 2019
@methane
methane deleted the ascii-fromstring branch June 24, 2019 03:30
lisroach pushed a commit to lisroach/cpython that referenced this pull request Sep 10, 2019
@methane @lisroach
bpo-37348: optimize decoding ASCII string (pythonGH-14283)
6634958 
`_PyUnicode_Writer` is a relatively complex structure.  Initializing it is significant overhead when decoding short ASCII string.
DinoV pushed a commit to DinoV/cpython that referenced this pull request Jan 14, 2020
@methane @DinoV
bpo-37348: optimize decoding ASCII string (pythonGH-14283)
04efd0d 
`_PyUnicode_Writer` is a relatively complex structure.  Initializing it is significant overhead when decoding short ASCII string.
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@methane @vstinner @brettcannon @the-knights-who-say-ni @bedevere-bot
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