Rust: Semaphores vs channels

results

running 2 tests
test with_channels   ... bench:    876410 ns/iter (+/- 655463)
test with_semaphores ... bench:    513476 ns/iter (+/- 711503)

test result: ok. 0 passed; 0 failed; 0 ignored; 2 measured

sem_vs_channel.rs

extern crate sync;
extern crate test;

use sync::{Semaphore, Arc};
use test::Bencher;

static TASK_COUNT: int = 10;

#[bench]
fn with_channels(b: &mut Bencher) {
    b.iter(|| {
        let (tx, rx) = channel();

        for _ in range(0, TASK_COUNT) {
          let task_tx = tx.clone();

          spawn(proc() {
            task_tx.send(());
          });
        }

        for _ in range(0, TASK_COUNT) {
          rx.recv();
        }
    });
}

#[bench]
fn with_semaphores(b: &mut Bencher) {
    b.iter(|| {
        let sem = Arc::new(Semaphore::new(TASK_COUNT));

        for _ in range(0, TASK_COUNT) {
            let task_sem = sem.clone();

            task_sem.acquire();
            spawn(proc() {
                task_sem.release();
            });
        }

        for _ in range(0, TASK_COUNT) {
            sem.acquire();
        }
    });
}