chore: set default parallel level for build_ext

[taegyunkim]

Sometimes we forget to set CMAKE_BUILD_PARALLEL_LEVEL as in https://github.com/DataDog/system-tests/pull/2876/files#diff-c8613d72fa796e8b51855229a46980f43859107cc8f8251839d13b11de883e15 or underlying tool makes it hard to set it correctly https://github.com/DataDog/dd-trace-py/pull/10129#discussion_r1708158004

This shaves off about ~1min from system-tests-build. Looks like build_wheels on mac are also faster with this.

Checklist

• [x] PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• [ ] Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[github-actions[bot]]

CODEOWNERS have been resolved as:

setup.py                                                                @DataDog/python-guild

[datadog-dd-trace-py-rkomorn[bot]]

Datadog Report

Branch report: taegyunkim/build-ext-default-parallel Commit report: 44595a5 Test service: dd-trace-py

:white_check_mark: 0 Failed, 175333 Passed, 1658 Skipped, 9h 58m 47.25s Total duration (10m 18.93s time saved) :hourglass: 1 Performance Regression

:hourglass: Performance Regressions vs Default Branch (1)

• test_service_override_env_var - test_kafka.py 45.12s (+41.32s, +1087%) - Details

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2024-08-13 05:32:05

Comparing candidate commit 44595a5ac7d6f98490bde55fe87103b57be10d7d in PR branch taegyunkim/build-ext-default-parallel with baseline commit b019b5007f002d0105bc810ee44444274ddf29c8 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 214 metrics, 2 unstable metrics.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 10.56%. Comparing base (7c42a03) to head (a2d32f1). Report is 6 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main   #10189       +/-   ##
===========================================
- Coverage   47.31%   10.56%   -36.75%     
===========================================
  Files        1425     1389       -36     
  Lines      129618   126304     -3314     
===========================================
- Hits        61324    13347    -47977     
- Misses      68294   112957    +44663     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.