Wide (Partitioned) Read Write Lock

This crate implements an enterprise-grade read-write lock, typically used for large data structures. The lock is internally 8x partitioned, which allows it to scale much better with a large number of readers, as compared to std::sync::RwLock.

Even though this is a large lock, it has better performance characteristic for uncontended single reader or single writer lock than std::sync::RwLock.

The lock uses a contiguous 576 byte heap area to store its state, so it's not a light-weight lock. If you have a complex data structure that holds a GB of data, this would be an appropriate lock.

An interesting feature of this lock, beside its performance, is its Read->Write upgrade mechanics. The ReadGuard allows an upgrade to a write-lock and informs the user whether the upgrade succeeded atomically or not. This enables the following pattern:

• Read to see if the data structure is in a particular state (e.g. contains a value).

  • if not, upgrade to a write lock
  • if upgrade was not atomic, perform the (potentially expensive) read again
  • write to the structure if needed

• Documentation

Usage

Add this to your Cargo.toml:

[dependencies]
widerwlock = "0.5"

and this to your crate root:

extern crate widerwlock;

Rust Version Support

The minimum supported Rust version is 1.28 due to use of allocator api.