| use test::black_box; |
| use test::Bencher; |
| |
| enum Cache { |
| L1, |
| L2, |
| L3, |
| } |
| |
| fn binary_search<F>(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::<Vec<_>>(); |
| 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::<Vec<_>>(); |
| 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]); |