1db3aa416c
* Simplify redundant doc-link * Remove impl of SeedableRng for SmallRng * Fix SeedableRng::Seed type for StdRng * SmallRng: do not expect thread_rng * Make SmallRng::from_thread_rng infallible * Fix benchmarks (SmallRng does not have from_entropy)
79 lines
2.6 KiB
Rust
79 lines
2.6 KiB
Rust
// Copyright 2021 Developers of the Rand project.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Implement benchmarks for uniform distributions over integer types
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use core::time::Duration;
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use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
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use rand::distributions::uniform::{SampleRange, Uniform};
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use rand::prelude::*;
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use rand_chacha::ChaCha8Rng;
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use rand_pcg::{Pcg32, Pcg64};
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const WARM_UP_TIME: Duration = Duration::from_millis(1000);
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const MEASUREMENT_TIME: Duration = Duration::from_secs(3);
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const SAMPLE_SIZE: usize = 100_000;
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const N_RESAMPLES: usize = 10_000;
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macro_rules! sample {
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($R:ty, $T:ty, $U:ty, $g:expr) => {
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$g.bench_function(BenchmarkId::new(stringify!($R), "single"), |b| {
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let mut rng = <$R>::from_rng(thread_rng()).unwrap();
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let x = rng.gen::<$U>();
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let bits = (<$T>::BITS / 2);
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let mask = (1 as $U).wrapping_neg() >> bits;
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let range = (x >> bits) * (x & mask);
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let low = <$T>::MIN;
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let high = low.wrapping_add(range as $T);
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b.iter(|| (low..=high).sample_single(&mut rng));
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});
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$g.bench_function(BenchmarkId::new(stringify!($R), "distr"), |b| {
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let mut rng = <$R>::from_rng(thread_rng()).unwrap();
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let x = rng.gen::<$U>();
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let bits = (<$T>::BITS / 2);
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let mask = (1 as $U).wrapping_neg() >> bits;
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let range = (x >> bits) * (x & mask);
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let low = <$T>::MIN;
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let high = low.wrapping_add(range as $T);
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let dist = Uniform::<$T>::new_inclusive(<$T>::MIN, high).unwrap();
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b.iter(|| dist.sample(&mut rng));
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});
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};
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($c:expr, $T:ty, $U:ty) => {{
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let mut g = $c.benchmark_group(concat!("sample", stringify!($T)));
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g.sample_size(SAMPLE_SIZE);
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g.warm_up_time(WARM_UP_TIME);
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g.measurement_time(MEASUREMENT_TIME);
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g.nresamples(N_RESAMPLES);
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sample!(SmallRng, $T, $U, g);
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sample!(ChaCha8Rng, $T, $U, g);
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sample!(Pcg32, $T, $U, g);
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sample!(Pcg64, $T, $U, g);
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g.finish();
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}};
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}
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fn sample(c: &mut Criterion) {
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sample!(c, i8, u8);
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sample!(c, i16, u16);
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sample!(c, i32, u32);
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sample!(c, i64, u64);
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sample!(c, i128, u128);
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}
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criterion_group! {
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name = benches;
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config = Criterion::default();
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targets = sample
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}
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criterion_main!(benches);
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