Pop loop vs. truncate

main.rs

#![feature(test)]
extern crate test;
use test::Bencher;

fn pop_loop(n: usize) -> Vec<usize> {
    let mut vec = (0..100).collect::<Vec<_>>();

    for _ in 0..n {
        vec.pop();
    }

    vec
}

fn truncating(n: usize) -> Vec<usize> {
    let mut vec = (0..100).collect::<Vec<_>>();

    let l = vec.len();
    vec.truncate(l - n);

    vec
}

#[bench]
fn bench_pop_loop(b: &mut Bencher) {
    let n = test::black_box(50);

    b.iter(|| pop_loop(n) )
}

#[bench]
fn bench_truncating(b: &mut Bencher) {
    let n = test::black_box(50);

    b.iter(|| truncating(n) )
}