bpo-36778: Avoid functools in encodings.cp65001 by vstinner · Pull Request #13110 · python/cpython (original) (raw)
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Replace functools.partial() with lambda to reduce the number of
imports at startup. Avoid the following imports at startup:
- _collections
- _functools
- _heapq
- _operator
- collections
- functools
- heapq
- itertools
- keyword
- operator
- reprlib
https://bugs.python.org/issue36778
| if not hasattr(codecs, 'code_page_encode'): |
| raise LookupError("cp65001 encoding is only available on Windows") |
| ### Codec APIs |
| encode = functools.partial(codecs.code_page_encode, 65001) |
| _decode = functools.partial(codecs.code_page_decode, 65001) |
| encode = lambda *args, **kw: codecs.code_page_encode(65001, *args, **kw) |
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Could you please measure how much overhead it adds?
Oh, my PR looks wrong. Most CP65001Test tests fail...
Oh, my PR looks wrong. Most CP65001Test tests fail...
I don't know if it helps, but test_startup_imports passes on IoT Core using this change with a default codepage of cp65001. So it looks like this strategy could work if there's a way to remove functools without breaking other things.
staticmethod is required, maybe.
Replace functools.partial() with lambda to reduce the number of imports at startup. Avoid the following imports at startup:
- _collections
- _functools
- _heapq
- _operator
- collections
- functools
- heapq
- itertools
- keyword
- operator
- reprlib
staticmethod is required, maybe.
Right. I fixed my PR with that. I also rebased my PR and added a NEWS entry.
@serhiy-storchaka: "Could you please measure how much overhead it adds?"
Benchmark in release mode:
>python -m venv env
>env\scripts\python_d.exe -m pip install perf
>env\scripts\python_d.exe -m perf timeit -s "import codecs; encode=codecs.lookup('cp65001').encode" "encode('')" -v -o ref.json
>git co master
>env\scripts\python_d.exe -m perf timeit -s "import codecs; encode=codecs.lookup('cp65001').encode" "encode('')" -v -o patch.json
env\scripts\python_d.exe -m perf compare_to ref.json patch.json
Mean +- std dev: [ref] 156 ns +- 3 ns -> [patch] 417 ns +- 17 ns: 2.68x slower (+168%)
I merged my PR #13230 instead.