# Amanieu/parking_lot

Compact and efficient synchronization primitives for Rust. Also provides an API for creating custom synchronization primitives.

Repository: https://github.com/Amanieu/parking_lot
Canonical: https://ross.abutalabs.com/products/parking_lot
Language: Rust
License: Apache-2.0
License Family: permissive
Last push: 2026-08-23T19:53:28+00:00

## Health v2 (maintenance only)
Score: 82/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 50, longevity 100
- inputs: {"age_days": 3764, "days_push": 10, "days_rel": 334, "gap_med": 0, "n_releases_24m": 6}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3400, forks 276 (observed 2026-08-28T04:08:02.804326+00:00)

## What it is
A Rust library providing compact, faster implementations of Mutex, RwLock, Condvar, Once, and ReentrantMutex compared to the standard library, plus a low-level API for building custom synchronization primitives. It achieves smaller memory footprints, inline fast paths, adaptive spinning, and fair locking policies.

## Use cases
- replace std::sync::Mutex for faster uncontended and contended locking
- reduce memory footprint of many fine-grained locks
- avoid reader/writer starvation with a fair RwLock
- get Condvar without spurious wakeups
- build custom synchronization primitives on a low-level parking API
- support Condvar/RwLock/Once on Windows XP

## When to choose
- your Rust application is bottlenecked on std synchronization primitives
- you need many small locks to increase parallelism
- you need guaranteed-fair RwLock or spurious-wakeup-free Condvar semantics

## When to avoid
- your workload is not concurrency-sensitive and std primitives suffice
- you want to minimize external dependencies in a small project

## Facets
- artifact type: library
- maturity: stable
- function: concurrency
- domain: developer-tools, performance
- platform: rust, cross-platform
- tags: mutex, rwlock, condvar, synchronization-primitives, lock-api

## Member repositories
- Amanieu/parking_lot (main) score 82

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:02.804326+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:38:42.288677+00:00, confidence not recorded.
  - readme: https://github.com/Amanieu/parking_lot (fetched 2026-08-28T04:08:02.804326+00:00, sha 010ce38ecfca)
  - registry_crates: https://crates.io/api/v1/crates/parking_lot (fetched 2026-08-29T09:32:42.499781+00:00, sha d92aac34617b)
- Data as of 2026-08-30T08:39:29.467469+00:00.