PFlock: Phase-Fair Reader-Writer Lock

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.

Example

use pflock::PFLock;

let lock = PFLock::new(5);

// many reader locks can be held at once
{
    let r1 = lock.read();
    let r2 = lock.read();
    assert_eq!(*r1, 5);
    assert_eq!(*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

@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}
}

C implementation

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.

RUSTFLAGS="--cfg c_reference" cargo test

License

All code is under the MIT license except for the C implementation in pflock_c/, which has its own license in the file.