use core::ptr::NonNull; use test::black_box; use test::Bencher; enum Cache { L1, L2, L3, } impl Cache { fn size(&self) -> usize { match self { Cache::L1 => 1000, // 8kb Cache::L2 => 10_000, // 80kb Cache::L3 => 1_000_000, // 8Mb } } } fn binary_search(b: &mut Bencher, cache: Cache, mapper: F) where F: Fn(usize) -> usize, { let size = cache.size(); 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()); }); } fn binary_search_worst_case(b: &mut Bencher, cache: Cache) { let size = cache.size(); let mut v = vec![0; size]; let i = 1; v[size - 1] = i; b.iter(move || { 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); } #[bench] fn binary_search_l1_worst_case(b: &mut Bencher) { binary_search_worst_case(b, Cache::L1); } #[bench] fn binary_search_l2_worst_case(b: &mut Bencher) { binary_search_worst_case(b, Cache::L2); } #[bench] fn binary_search_l3_worst_case(b: &mut Bencher) { binary_search_worst_case(b, Cache::L3); } #[derive(Clone)] struct Rgb(u8, u8, u8); impl Rgb { fn gen(i: usize) -> Self { Rgb(i as u8, (i as u8).wrapping_add(7), (i as u8).wrapping_add(42)) } } macro_rules! rotate { ($fn:ident, $n:expr, $mapper:expr) => { #[bench] fn $fn(b: &mut Bencher) { let mut x = (0usize..$n).map(&$mapper).collect::>(); b.iter(|| { for s in 0..x.len() { x[..].rotate_right(s); } black_box(x[0].clone()) }) } }; } rotate!(rotate_u8, 32, |i| i as u8); rotate!(rotate_rgb, 32, Rgb::gen); rotate!(rotate_usize, 32, |i| i); rotate!(rotate_16_usize_4, 16, |i| [i; 4]); rotate!(rotate_16_usize_5, 16, |i| [i; 5]); rotate!(rotate_64_usize_4, 64, |i| [i; 4]); rotate!(rotate_64_usize_5, 64, |i| [i; 5]); macro_rules! swap_with_slice { ($fn:ident, $n:expr, $mapper:expr) => { #[bench] fn $fn(b: &mut Bencher) { let mut x = (0usize..$n).map(&$mapper).collect::>(); let mut y = ($n..($n * 2)).map(&$mapper).collect::>(); let mut skip = 0; b.iter(|| { for _ in 0..32 { x[skip..].swap_with_slice(&mut y[..($n - skip)]); skip = black_box(skip + 1) % 8; } black_box((x[$n / 3].clone(), y[$n * 2 / 3].clone())) }) } }; } swap_with_slice!(swap_with_slice_u8_30, 30, |i| i as u8); swap_with_slice!(swap_with_slice_u8_3000, 3000, |i| i as u8); swap_with_slice!(swap_with_slice_rgb_30, 30, Rgb::gen); swap_with_slice!(swap_with_slice_rgb_3000, 3000, Rgb::gen); swap_with_slice!(swap_with_slice_usize_30, 30, |i| i); swap_with_slice!(swap_with_slice_usize_3000, 3000, |i| i); swap_with_slice!(swap_with_slice_4x_usize_30, 30, |i| [i; 4]); swap_with_slice!(swap_with_slice_4x_usize_3000, 3000, |i| [i; 4]); swap_with_slice!(swap_with_slice_5x_usize_30, 30, |i| [i; 5]); swap_with_slice!(swap_with_slice_5x_usize_3000, 3000, |i| [i; 5]); #[bench] fn fill_byte_sized(b: &mut Bencher) { #[derive(Copy, Clone)] struct NewType(u8); let mut ary = [NewType(0); 1024]; b.iter(|| { let slice = &mut ary[..]; black_box(slice.fill(black_box(NewType(42)))); }); } // Tests the ability of the compiler to recognize that only the last slice item is needed // based on issue #106288 #[bench] fn fold_to_last(b: &mut Bencher) { let slice: &[i32] = &[0; 1024]; b.iter(|| black_box(slice).iter().fold(None, |_, r| Some(NonNull::from(r)))); }