use test::black_box; use test::Bencher; enum Cache { L1, L2, L3, } fn binary_search(b: &mut Bencher, cache: Cache, mapper: F) where F: Fn(usize) -> usize, { let size = match cache { Cache::L1 => 1000, // 8kb Cache::L2 => 10_000, // 80kb Cache::L3 => 1_000_000, // 8Mb }; let v = (0..size).map(&mapper).collect::>(); let mut r = 0usize; b.iter(move || { // LCG constants from https://en.wikipedia.org/wiki/Numerical_Recipes. r = r.wrapping_mul(1664525).wrapping_add(1013904223); // Lookup the whole range to get 50% hits and 50% misses. let i = mapper(r % size); black_box(v.binary_search(&i).is_ok()); }) } #[bench] fn binary_search_l1(b: &mut Bencher) { binary_search(b, Cache::L1, |i| i * 2); } #[bench] fn binary_search_l2(b: &mut Bencher) { binary_search(b, Cache::L2, |i| i * 2); } #[bench] fn binary_search_l3(b: &mut Bencher) { binary_search(b, Cache::L3, |i| i * 2); } #[bench] fn binary_search_l1_with_dups(b: &mut Bencher) { binary_search(b, Cache::L1, |i| i / 16 * 16); } #[bench] fn binary_search_l2_with_dups(b: &mut Bencher) { binary_search(b, Cache::L2, |i| i / 16 * 16); } #[bench] fn binary_search_l3_with_dups(b: &mut Bencher) { binary_search(b, Cache::L3, |i| i / 16 * 16); } macro_rules! rotate { ($fn:ident, $n:expr, $mapper:expr) => { #[bench] fn $fn(b: &mut Bencher) { let mut x = (0usize..$n).map(&$mapper).collect::>(); b.iter(|| { for s in 0..x.len() { x[..].rotate_right(s); } black_box(x[0].clone()) }) } }; } #[derive(Clone)] struct Rgb(u8, u8, u8); rotate!(rotate_u8, 32, |i| i as u8); rotate!(rotate_rgb, 32, |i| Rgb(i as u8, (i as u8).wrapping_add(7), (i as u8).wrapping_add(42))); rotate!(rotate_usize, 32, |i| i); rotate!(rotate_16_usize_4, 16, |i| [i; 4]); rotate!(rotate_16_usize_5, 16, |i| [i; 5]); rotate!(rotate_64_usize_4, 64, |i| [i; 4]); rotate!(rotate_64_usize_5, 64, |i| [i; 5]);