lagoon's Introduction

Lagoon

Lagoon is a thread pool crate that aims to address many of the problems with existing thread pool crates.

Example

Lagoon's scoped jobs can be used for simple rayon-like data parallelism.

// A vector of the numbers 0 to 99
let mut data = (0..100).collect::<Vec<u32>>();

lagoon::ThreadPool::default().scoped(|s| {
    // For each element in the vector...
    for x in data.iter_mut() {
        // ...spawn a job that squares that element
        s.run(move || *x *= *x);
    }
});

// Demonstrate that the elements have indeed been squared
assert!((0..100)
    .map(|x| x * x)
    .zip(data.into_iter())
    .all(|(x, y)| x == y));

Features

Scoped jobs: Safely spawn jobs that have access to their parent scope!
Job handles: Receive the result of a job when it finishes, or wait on it to finish!
Global pool: A pay-for-what-you-use global thread pool that avoids dependencies fighting over resources!
Customise thread attributes: Specify thread name, stack size, etc.

Planned Features

Async support for job waiting: Use the thread pool in an async context!

Performance

Lagoon has very competitive performance. Below are timings required for each thread pool crate to spawn a new pool, execute 100,000 trivial jobs, and then finish executing (i.e: smaller is better) compared to common alternative crates.

Spawning 100000 trivial tasks/lagoon     time:   [15.124 ms 16.437 ms 17.871 ms]
Spawning 100000 trivial tasks/threadpool time:   [59.108 ms 59.549 ms 59.989 ms]
Spawning 100000 trivial tasks/uvth       time:   [11.494 ms 12.598 ms 13.750 ms]
Spawning 100000 trivial tasks/rusty_pool time:   [40.203 ms 44.778 ms 49.612 ms]

Benchmarks were run on an AMD Ryzen 7 3700x with 16 threads.