This library provides a phase-fair reader-writer lock, as described in the paper "Reader-Writer Synchronization for Shared-Memory Multiprocessor Real-Time Systems". by Brandenburg et. al.
Reader preference, writer preference, and task-fair reader-writer locks are shown to cause undue blocking in multiprocessor real-time systems. A new phase-fair reader-writer lock is proposed as an alternative that significantly reduces worst-case blocking for readers.
```rust use pflock::PFLock;
let lock = PFLock::new(5);
// many reader locks can be held at once { let r1 = lock.read(); let r2 = lock.read(); asserteq!(*r1, 5); asserteq!(*r2, 5); } // read locks are dropped at this point
// only one write lock may be held, however { let mut w = lock.write(); w += 1; assert_eq!(w, 6); } // write lock is dropped here ```
latex
@inproceedings{brandenburg2009reader,
title={Reader-writer synchronization for shared-memory multiprocessor real-time systems},
author={Brandenburg, Bj{\"o}rn B and Anderson, James H},
booktitle={2009 21st Euromicro Conference on Real-Time Systems},
pages={184--193},
year={2009},
organization={IEEE}
}
A reference implementation in C is provided in the branch
cnord/ffi in the
directory pflock_c/.
Run tests with the reference implementation using RUSTFLAGS="--cfg
c_reference", e.g.
bash
RUSTFLAGS="--cfg c_reference" cargo test
All code is under the MIT license except for the C implementation in pflock_c/, which has its own license in the file.