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[mypyc] Optimize str.encode with specializations for common used encodings by svalentin · Pull Request #18232 · python/mypy · GitHub
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[mypyc] Optimize str.encode with specializations for common used encodings #18232

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Merged
merged 3 commits into from
Dec 3, 2024
Merged

[mypyc] Optimize str.encode with specializations for common used encodings #18232

merged 3 commits into from
Dec 3, 2024

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svalentin
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Tested with:

import time
start = time.time()
for i in range(20000000):
    "test".encode('utf-8')
print(time.time() - start)

With PR applied and running mypyc, python3 -c "import test" runs in:
0.5383486747741699
0.5224344730377197
0.555696964263916

Without PR applied:
0.7315819263458252
0.7105758190155029
0.7471706867218018

Similar times observed for "ascii"

@svalentin svalentin requested a review from JukkaL December 2, 2024 18:19
JukkaL
JukkaL reviewed Dec 3, 2024
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I think some cases aren't covered by the logic. Suggested some test cases that should help.

mypyc/test-data/irbuild-str.test
s.encode('utf-8', errors='strict')
s.encode('utf-8', 'backslashreplace')
s.encode(encoding='ascii')
s.encode('ascii', 'backslashreplace')
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Also test cases where the specialization shouldn't be applied. Examples: s.encode(x), s.encode('a', x), s.encode('utf8', errors=x) and s.encode(errors=x) where x is not a literal.

Test cases where we have two keyword args: s.encode(encoding=..., errors=...) and s.encode(errors=..., encoding=...).

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I've updated the logic to work out the args better and added more tests. Please take another look!

JukkaL
JukkaL approved these changes Dec 3, 2024
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Looks good, thanks!

@JukkaL JukkaL merged commit e731185 into python:master Dec 3, 2024
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@svalentin svalentin deleted the mypyc-str-encode branch December 17, 2024 16:27
@JukkaL JukkaL mentioned this pull request Aug 19, 2025
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JukkaL added a commit that referenced this pull request Aug 19, 2025
@JukkaL
[mypyc] Specialize bytes.decode calls with common encodings (#19688)
68809c0 
This is similar to #18232, which specialized `encode`.

A micro-benchmark that calls `decode` repeatedly was up to 45% faster.
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@JukkaL JukkaL JukkaL approved these changes

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@svalentin @JukkaL