gh-118761: Improve import time by lazy import of `traceback` #129811

donBarbos · 2025-02-07T15:01:49Z

TODO:

Improve import time modules by lazy import traceback
Remove unused import fcntl

CPython configure flags:

./configure --enable-optimizations --with-lto --enable-loadable-sqlite-extensions

Hyperfine benchmark for `import traceback`:

$ hyperfine --warmup 11 "./python -c 'import traceback'"
Benchmark 1: ./python -c 'import traceback'
  Time (mean ± σ):      17.0 ms ±   0.5 ms    [User: 14.2 ms, System: 2.7 ms]
  Range (min … max):    16.5 ms …  22.7 ms    167 runs

Hyperfine benchmarks for updated modules:

import `_pyrepl` experiments (no diff)

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 --runs 3000 "./python -c 'import _pyrepl'"
Benchmark 1: ./python -c 'import _pyrepl'
  Time (mean ± σ):       9.2 ms ±   0.4 ms    [User: 7.3 ms, System: 1.8 ms]
  Range (min … max):     8.6 ms …  14.7 ms    3000 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 --runs 3000 "./python -c 'import _pyrepl'"
Benchmark 1: ./python -c 'import _pyrepl'
  Time (mean ± σ):       9.3 ms ±   0.3 ms    [User: 7.4 ms, System: 1.8 ms]
  Range (min … max):     8.7 ms …  14.7 ms    3000 runs

import `code` experiments

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 --runs 3000 "./python -c 'import code'"
Benchmark 1: ./python -c 'import code'
  Time (mean ± σ):      10.0 ms ±   0.5 ms    [User: 8.2 ms, System: 1.8 ms]
  Range (min … max):     9.3 ms …  15.8 ms    3000 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 --runs 3000 "./python -c 'import code'"
Benchmark 1: ./python -c 'import code'
  Time (mean ± σ):      17.8 ms ±   0.8 ms    [User: 14.9 ms, System: 2.9 ms]
  Range (min … max):    17.0 ms …  28.7 ms    3000 runs

import `doctest` experiments (no diff)

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 "./python -c 'import doctest'"
Benchmark 1: ./python -c 'import doctest'
  Time (mean ± σ):      34.8 ms ±   0.3 ms    [User: 30.2 ms, System: 4.6 ms]
  Range (min … max):    34.2 ms …  35.7 ms    84 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 "./python -c 'import doctest'"
Benchmark 1: ./python -c 'import doctest'
  Time (mean ± σ):      35.6 ms ±   0.5 ms    [User: 30.8 ms, System: 4.8 ms]
  Range (min … max):    34.9 ms …  37.9 ms    81 runs

import `logging` experiments (no diff)

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 --runs 2000 "./python -c 'import logging'"
Benchmark 1: ./python -c 'import logging'
  Time (mean ± σ):      20.9 ms ±   0.7 ms    [User: 17.7 ms, System: 3.1 ms]
  Range (min … max):    20.1 ms …  32.7 ms    2000 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 --runs 2000 "./python -c 'import logging'"
Benchmark 1: ./python -c 'import logging'
  Time (mean ± σ):      20.7 ms ±   0.5 ms    [User: 17.7 ms, System: 3.0 ms]
  Range (min … max):    20.0 ms …  30.8 ms    2000 runs

import `pdb` experiments (no diff)

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 --runs 2000 "./python -c 'import pdb'"
Benchmark 1: ./python -c 'import pdb'
  Time (mean ± σ):      29.3 ms ±   0.9 ms    [User: 25.0 ms, System: 4.2 ms]
  Range (min … max):    28.2 ms …  37.9 ms    2000 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 --runs 2000 "./python -c 'import pdb'"
Benchmark 1: ./python -c 'import pdb'
  Time (mean ± σ):      30.1 ms ±   1.3 ms    [User: 25.9 ms, System: 4.2 ms]
  Range (min … max):    28.8 ms …  44.2 ms    2000 runs

import `py_compile` experiments

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 --runs 2000 "./python -c 'import py_compile'"
Benchmark 1: ./python -c 'import py_compile'
  Time (mean ± σ):      11.7 ms ±   0.5 ms    [User: 9.6 ms, System: 2.0 ms]
  Range (min … max):    10.9 ms …  19.5 ms    2000 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 "./python -c 'import py_compile'"
Benchmark 1: ./python -c 'import py_compile'
  Time (mean ± σ):      18.2 ms ±   0.5 ms    [User: 15.4 ms, System: 2.7 ms]
  Range (min … max):    17.4 ms …  21.0 ms    159 runs

import `pydoc` experiments

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 "./python -c 'import pydoc'"
Benchmark 1: ./python -c 'import pydoc'
  Time (mean ± σ):      32.6 ms ±   0.4 ms    [User: 28.4 ms, System: 4.2 ms]
  Range (min … max):    31.8 ms …  34.3 ms    87 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 "./python -c 'import pydoc'"
Benchmark 1: ./python -c 'import pydoc'
  Time (mean ± σ):      34.3 ms ±   0.3 ms    [User: 30.2 ms, System: 4.1 ms]
  Range (min … max):    33.5 ms …  35.2 ms    84 runs

import `unittest` experiments

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 "./python -c 'import unittest'"
Benchmark 1: ./python -c 'import unittest'
  Time (mean ± σ):      21.9 ms ±   0.3 ms    [User: 18.4 ms, System: 3.4 ms]
  Range (min … max):    21.3 ms …  22.8 ms    133 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 "./python -c 'import unittest'"
Benchmark 1: ./python -c 'import unittest'
  Time (mean ± σ):      23.3 ms ±   0.3 ms    [User: 19.5 ms, System: 3.7 ms]
  Range (min … max):    22.6 ms …  24.3 ms    123 runs

import `xmlrpc` experiments (no diff)

➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 --runs 3000 "./python -c 'import xmlrpc'"
Benchmark 1: ./python -c 'import xmlrpc'
  Time (mean ± σ):       9.1 ms ±   0.4 ms    [User: 7.3 ms, System: 1.8 ms]
  Range (min … max):     8.7 ms …  14.6 ms    3000 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 --runs 3000 "./python -c 'import xmlrpc'"
Benchmark 1: ./python -c 'import xmlrpc'
  Time (mean ± σ):       9.1 ms ±   0.4 ms    [User: 7.4 ms, System: 1.7 ms]
  Range (min … max):     8.6 ms …  19.6 ms    3000 runs
➜  cpython git:(lazy-imports-traceback) ✗ hyperfine --warmup 11 "./python -c 'import xmlrpc'"
Benchmark 1: ./python -c 'import xmlrpc'
  Time (mean ± σ):       8.8 ms ±   0.6 ms    [User: 7.3 ms, System: 1.5 ms]
  Range (min … max):     8.3 ms …  14.5 ms    277 runs
➜  cpython git:(3d3a4beefe) ✗ hyperfine --warmup 11 "./python -c 'import xmlrpc'"
Benchmark 1: ./python -c 'import xmlrpc'
  Time (mean ± σ):       8.7 ms ±   0.2 ms    [User: 7.4 ms, System: 1.4 ms]
  Range (min … max):     8.2 ms …   9.8 ms    303 runs

Issue: Improve import time of various stdlib modules #118761

picnixz · 2025-02-07T15:26:19Z

traceback is generally used in conjunction with other debugging modules, so I'm not sure it's worth the change. I'd like to mention that I also benchmark the import times using -X importtime as they don't suffer from startup time. Now, if we don't see improvements overall, I don't think we should actually do the change. I only changed modules for which import time is reduced by at least 20% (using -X importtime) or where we gain something noticeable on hyperfine. Most of your results show <10% improvements or no changes at all, so I don't think we need to do this. We definitely don't want to make all imports as lazy IMO.

Misc/NEWS.d/next/Library/2025-02-07-17-04-08.gh-issue-118761.hkNOEA.rst

…kNOEA.rst Co-authored-by: Peter Bierma <zintensitydev@gmail.com>

AA-Turner · 2025-02-07T15:44:16Z

Please see my comment in your other PR, and also Benedikt's above.

A

donBarbos · 2025-02-16T00:47:27Z

Ok, i realized that this PR was a mistake and i will improve import time of each module separately. Maybe i will send PR for same module but without some other imports

Always lazy import traceback

1fb0687

donBarbos requested review from gaogaotiantian, vsajip, pablogsal, lysnikolaou and ambv as code owners February 7, 2025 15:01

bedevere-app bot added the awaiting review label Feb 7, 2025

bedevere-app bot mentioned this pull request Feb 7, 2025

Improve import time of various stdlib modules #118761

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ZeroIntensity requested a review from picnixz February 7, 2025 15:08

ZeroIntensity reviewed Feb 7, 2025

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…kNOEA.rst Co-authored-by: Peter Bierma <zintensitydev@gmail.com>

AA-Turner added the DO-NOT-MERGE label Feb 7, 2025

picnixz changed the title ~~gh-118761: Improve import time by lazy import of traceback~~ gh-118761: Improve import time by lazy import of traceback Feb 8, 2025

donBarbos closed this Feb 16, 2025

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gh-118761: Improve import time by lazy import of `traceback` #129811

gh-118761: Improve import time by lazy import of `traceback` #129811

donBarbos commented Feb 7, 2025 •

edited by bedevere-app bot

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picnixz commented Feb 7, 2025 •

edited

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AA-Turner commented Feb 7, 2025

donBarbos commented Feb 16, 2025 •

edited

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gh-118761: Improve import time by lazy import of traceback #129811

gh-118761: Improve import time by lazy import of traceback #129811

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donBarbos commented Feb 7, 2025 • edited by bedevere-app bot Loading

TODO:

CPython configure flags:

Hyperfine benchmark for import traceback:

Hyperfine benchmarks for updated modules:

import _pyrepl experiments (no diff)

import code experiments

import doctest experiments (no diff)

import logging experiments (no diff)

import pdb experiments (no diff)

import py_compile experiments

import pydoc experiments

import unittest experiments

import xmlrpc experiments (no diff)

picnixz commented Feb 7, 2025 • edited Loading

AA-Turner commented Feb 7, 2025

donBarbos commented Feb 16, 2025 • edited Loading

gh-118761: Improve import time by lazy import of `traceback` #129811

gh-118761: Improve import time by lazy import of `traceback` #129811

donBarbos commented Feb 7, 2025 •

edited by bedevere-app bot

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Hyperfine benchmark for `import traceback`:

import `_pyrepl` experiments (no diff)

import `code` experiments

import `doctest` experiments (no diff)

import `logging` experiments (no diff)

import `pdb` experiments (no diff)

import `py_compile` experiments

import `pydoc` experiments

import `unittest` experiments

import `xmlrpc` experiments (no diff)

picnixz commented Feb 7, 2025 •

edited

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donBarbos commented Feb 16, 2025 •

edited

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