diff options
Diffstat (limited to 'library/alloc/benches/binary_heap.rs')
-rw-r--r-- | library/alloc/benches/binary_heap.rs | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/library/alloc/benches/binary_heap.rs b/library/alloc/benches/binary_heap.rs new file mode 100644 index 000000000..917e71f25 --- /dev/null +++ b/library/alloc/benches/binary_heap.rs @@ -0,0 +1,91 @@ +use std::collections::BinaryHeap; + +use rand::seq::SliceRandom; +use test::{black_box, Bencher}; + +#[bench] +fn bench_find_smallest_1000(b: &mut Bencher) { + let mut rng = crate::bench_rng(); + let mut vec: Vec<u32> = (0..100_000).collect(); + vec.shuffle(&mut rng); + + b.iter(|| { + let mut iter = vec.iter().copied(); + let mut heap: BinaryHeap<_> = iter.by_ref().take(1000).collect(); + + for x in iter { + let mut max = heap.peek_mut().unwrap(); + // This comparison should be true only 1% of the time. + // Unnecessary `sift_down`s will degrade performance + if x < *max { + *max = x; + } + } + + heap + }) +} + +#[bench] +fn bench_peek_mut_deref_mut(b: &mut Bencher) { + let mut bheap = BinaryHeap::from(vec![42]); + let vec: Vec<u32> = (0..1_000_000).collect(); + + b.iter(|| { + let vec = black_box(&vec); + let mut peek_mut = bheap.peek_mut().unwrap(); + // The compiler shouldn't be able to optimize away the `sift_down` + // assignment in `PeekMut`'s `DerefMut` implementation since + // the loop might not run. + for &i in vec.iter() { + *peek_mut = i; + } + // Remove the already minimal overhead of the sift_down + std::mem::forget(peek_mut); + }) +} + +#[bench] +fn bench_from_vec(b: &mut Bencher) { + let mut rng = crate::bench_rng(); + let mut vec: Vec<u32> = (0..100_000).collect(); + vec.shuffle(&mut rng); + + b.iter(|| BinaryHeap::from(vec.clone())) +} + +#[bench] +fn bench_into_sorted_vec(b: &mut Bencher) { + let bheap: BinaryHeap<i32> = (0..10_000).collect(); + + b.iter(|| bheap.clone().into_sorted_vec()) +} + +#[bench] +fn bench_push(b: &mut Bencher) { + let mut bheap = BinaryHeap::with_capacity(50_000); + let mut rng = crate::bench_rng(); + let mut vec: Vec<u32> = (0..50_000).collect(); + vec.shuffle(&mut rng); + + b.iter(|| { + for &i in vec.iter() { + bheap.push(i); + } + black_box(&mut bheap); + bheap.clear(); + }) +} + +#[bench] +fn bench_pop(b: &mut Bencher) { + let mut bheap = BinaryHeap::with_capacity(10_000); + + b.iter(|| { + bheap.extend((0..10_000).rev()); + black_box(&mut bheap); + while let Some(elem) = bheap.pop() { + black_box(elem); + } + }) +} |