Crossbeam-STM

Crossbeam-STM is a Software Transactional Memory implementation using crossbeam-epoch for memory reclamation. It is meant to be as fast and consistent as possible for load speed, at the expense of having inconsistent-timed and potentially very slow writes.

*THIS PROJECT IS NOT READY FOR GENERAL USAGE.*

Example

```rust extern crate crossbeam_stm;

use crossbeam_stm::Stm;

// Create a new STM pointer with a Vec of numbers let stm = Stm::new(vec![1,2,3,4]);

// Read from the STM { let data = stm.load(); println!("Current STM: {:?}", data); }

// Update the STM pointer to add a new number stm.update(|old| { let mut new = old.clone(); new.push(5); new });

// Read the new data { let data = stm.load(); println!("Current STM: {:?}", data); }

```

Benchmarks

Note that these benchmarks exist without any contention.

Under contention: - Crossbeam-STM's load will always be constant-time. - Crossbeam-STM's write will slow down if multiple threads attempt to write at the same time. ``` // Crossbeam-STM test cbstmload ... bench: 12 ns/iter (+/- 0) test cbstmupdate ... bench: 686 ns/iter (+/- 7)

// RwLock in stdlib test rwlockload ... bench: 48 ns/iter (+/- 0) test rwlockupdate ... bench: 36 ns/iter (+/- 0)

// RwLock in parkinglot test plrwlockload ... bench: 21 ns/iter (+/- 0) test plrwlock_update ... bench: 13 ns/iter (+/- 0) ```

License

Licensed under the terms of the MIT license and the Apache License (Version 2.0)

See LICENSE-MIT and LICENSE-APACHE for details.