threadpoolctl

threadpoolctl Permissive license BSD-3-Clause Active ★ 431 v3.6.0 released 2025-03-13

Install

threadpoolctl on PyPI

pip

pip install threadpoolctl

uv

uv add threadpoolctl

poetry

poetry add threadpoolctl

Package facts

License	BSD-3-Clause (permissive)
Python support	supports the current Python release (>=3.9)
Install friction	low — pure-Python wheel
Runtime dependencies	none
Maintenance	actively maintained — 518 days since the last release
Last repo commit	2026-08-11
First released	2019-06-03
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: threadpoolctl-3.6.0-py3-none-any.whl

Intended Audience :: DevelopersLicense :: OSI Approved :: BSD LicenseProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.9Topic :: Software Development :: Libraries :: Python Modules

About threadpoolctl

from the package's own PyPI description — quoted content, verbatim

Thread-pool Controls Build Status (image) codecov (image)

Python helpers to limit the number of threads used in the threadpool-backed of common native libraries used for scientific computing and data science (e.g. BLAS and OpenMP).

Fine control of the underlying thread-pool size can be useful in workloads that involve nested parallelism so as to mitigate oversubscription issues.

Installation

For users, install the last published version from PyPI:

bash pip install threadpoolctl

For contributors, install from the source repository in developer mode:

bash pip install -r dev-requirements.txt flit install --symlink

then you run the tests with pytest:

bash pytest

Usage

Command Line Interface

Get a JSON description of thread-pools initialized when importing python packages such as numpy or scipy for instance:

``` python -m threadpoolctl -i...

Read as markdown · JSON record · Source repository · Homepage

AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

Inspect and control the thread-pool size of native libraries like BLAS and OpenMP, preventing thread oversubscription in nested parallel workloads.

Minimal install friction: pure-Python wheel with zero runtime dependencies and active maintenance (last release 2025-03-13, 431 GitHub stars).

BSD-3-Clause permissive license allows use in most contexts without restriction, including commercial and proprietary projects.

Usage

pip install threadpoolctl

from threadpoolctl import threadpool_limits

with threadpool_limits(limits=1, user_api='blas'):
    # Calls to BLAS implementations will be limited to one thread

Verdict: Lightweight, actively maintained utility for controlling thread pools in scientific computing libraries. No security vulnerabilities, permissive license, and zero dependencies make it a safe dependency for projects needing fine-grained parallelism control.

Needs verification

Performance impact of threadpool limiting on real-world workloads
Compatibility with all BLAS implementations across different platforms

thread pool controllimit threads blas openmpnested parallelism oversubscriptionthreadpool introspectioncontrol native library threadsparallel workload thread managementthread limiting scientific computing