ieu

ieu is a package for simple, minimal overhead (a handful of atomics at startup, one for each iteration) parallel execution of a function over a series of indices. It is designed for use in situations with few calls to execute on the thread pool (due to the relatively high overhead compared to other solutions, ieu doesn't use a spin-lock so takes 10-15 microseconds to wake each thread) but each call to execute is expensive so can benefit from the low per iteration overhead.

Usage

ieu provides a global thread pool constructed on demand using the environment variables IEU_NUM_THREADS, RAYON_NUM_THREADS (if IEU_NUM_THREADS is not set), or the number of CPU threads on teh system if neither is set.

// run on the global thread
ieu::execute(
    3,
    |i| {
        // i ranges 0..3
        println!("Hello from iteration {}", i);
    },
);

ieu also allows you to create custom thread pools with varying numbers of threads. This is useful for testing or if you want to use a different number of threads for different parts of your program.

// create a thread pool with 4 threads
let mut pool = ieu::Pool::new(4);

// run on the custom thread pool
pool.execute(
    3,
    |i| {
        // i ranges 0..3
        println!("Hello from iteration {}", i);
    },
);

Important Note

ieu is not a general purpose thread pool like rayon, it's designed to run a single expensive task at a time, not many tasks from many sources. Each call to execute will block the current thread and lock the thread pool until the task is complete.