pythonpython-pillow/Pillow #8971Not a task: not reproduced

Parallel build is no longer parallel

envgap__python-pillow__Pillow-8971

Original GitHub issue ↗Dated source checkout ↗Opened 2025-05-23

01 / FAILURE SIGNATURE

As reported upstream

No identifying execution failure has been captured.

Not a benchmark task.

In a clean container the reported failure did not reproduce, or the known fix did not make the project run.

02 / ENVIRONMENT RECIPE

Base commit: 84855d11c8fd790d89507ac1c51a5e393178477a
Manifest: pyproject.toml
Reproduce: Awaiting issue-specific recipe
Run under trace: Awaiting a meaningful runtime command

03 / ORIGINAL ISSUE TEXT

python-pillow/Pillow #8971 · read the original issue

### What did you do?

`make debug` or `make install`

### What did you expect to happen?

Expect compilation to happen across all the cores, taking ~ 2-3 seconds.

### What actually happened?

Single threaded, taking ~15 seconds. There are something like 60 compilation units, and I have at least 8 cores.

### What are your OS, Python and Pillow versions?

* OS: Mac + Linux
* Python: 3.12
* Pillow: 11.2, main

Sometime between ~6 years ago and now, probably when the setuptools migrated around or we went to the newer build tool specifications, the parallel option here: https://github.com/python-pillow/Pillow/blob/main/setup.py#L381 stopped working. 

I can confirm that the code there is running, `self.parallel` is set correctly, but setuptools is apparently not using it anymore.

Continue on GitHub ↗

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