gh-118761: Improve import time for csv

[picnixz]

Benchmarks are for a release non-PGO build (PR) against a PGO build (main). This will be the last PR for that issue.

Note

Considering that csv is used in many applications, I think this improvement makes sense (especially for data scientists).

PR

$ ./python -X importtime -c 'import csv' import time: self [us] | cumulative | imported package ... import time: 229 | 229 | linecache import time: 331 | 331 | types import time: 175 | 175 | _csv import time: 629 | 1134 | csv

$ hyperfine --warmup 8 "./python -c 'import csv'" Benchmark 1: ./python -c 'import csv' Time (mean ± σ): 5.9 ms ± 0.4 ms [User: 5.0 ms, System: 1.0 ms] Range (min … max): 5.5 ms … 11.0 ms 452 runs

Main

$ ./python -X importtime -c 'import csv' import time: self [us] | cumulative | imported package ... import time: 227 | 227 | linecache import time: 261 | 261 | types import time: 1419 | 1680 | enum import time: 62 | 62 | _sre import time: 218 | 218 | re._constants import time: 327 | 544 | re._parser import time: 79 | 79 | re._casefix import time: 287 | 971 | re._compiler import time: 90 | 90 | itertools import time: 86 | 86 | keyword import time: 46 | 46 | _operator import time: 187 | 233 | operator import time: 119 | 119 | reprlib import time: 45 | 45 | _collections import time: 733 | 1304 | collections import time: 39 | 39 | _functools import time: 498 | 1840 | functools import time: 114 | 114 | copyreg import time: 426 | 5029 | re import time: 107 | 107 | _csv import time: 575 | 5709 | csv

$ hyperfine --warmup 8 "./python -c 'import csv'" Benchmark 1: ./python -c 'import csv' Time (mean ± σ): 9.2 ms ± 0.9 ms [User: 8.0 ms, System: 1.2 ms] Range (min … max): 8.4 ms … 16.7 ms 297 runs

• Issue: Improve import time of various stdlib modules #118761

[vstinner]

LGTM

[picnixz]

In a few hours, I will leave until Friday, but I'd like Adam or Hugo to review my English. Feel free to merge this PR and freely update it (otherwise, I'll do it once I'm back).

[hugovk]

Looks good, thanks!