ProTier

Protier is a lightweight, open‑source priority queue library written in Python and Rust. It was first released in 2018 by the developer consortium OpenPriority, and its goal is to offer a deterministic, lock‑free data structure for concurrent environments. The core of Protier is a binary heap implementation that supports both static and dynamic priorities and can be extended with custom comparator functions. The Rust implementation targets embedded and IoT devices, whereas the Python version is frequently used in data‑processing pipelines and machine‑learning training loops.

The library exposes a simple API: `push(item, priority)`, `pop()`, and `peek()` methods for accessing the highest‑priority element without removal. It also includes advanced features such as priority tagging, batch‑updates, and read‑only iterators that preserve thread safety. Protier was designed to satisfy the latency requirements of real‑time systems; benchmarks published on the project’s GitHub repository show that it achieves sub‑microsecond operations on an 8‑core CPU.

Protier is integrated into several open‑source projects. In the AI‑DevKit suite it manages token‑generation jobs, while the open‑source network simulator ns‑3 uses Protier to schedule packet transmissions. The library supports both CPython and PyPy, and its module can be compiled into a shared library that is callable from C and Java via the foreign‑function interface.

The development of Protier is governed by a contributor license agreement under the Apache 2.0 license. Its source code is hosted on GitHub, where the community follows a pull‑request workflow. Documentation is available on ReadTheDocs, and a mailing list is maintained for distribution‑level support. The project’s roadmap emphasizes scalability, cross‑platform PGO optimizations, and the addition of a monotonic‑queue variant for bounded‑size workloads.