Skip to content

Commit

Permalink
Add a benchmark for UniformInt sample_single
Browse files Browse the repository at this point in the history
  • Loading branch information
@jongiddy
jongiddy committed Jul 18, 2020
1 parent 1d54f11 commit c337164
Showing 1 changed file with 205 additions and 6 deletions.
211 changes: 205 additions & 6 deletions benches/distributions.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,10 +17,11 @@ extern crate test;
const RAND_BENCH_N: u64 = 1000;

use rand::distributions::{Alphanumeric, Open01, OpenClosed01, Standard, Uniform};
use rand::distributions::uniform::{UniformInt, UniformSampler};
use std::mem::size_of;
use std::num::{NonZeroU128, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8};
use std::time::Duration;
use test::Bencher;
use test::{Bencher, black_box};

use rand::prelude::*;

Expand Down Expand Up @@ -207,11 +208,22 @@ macro_rules! gen_range_int {
};
}

gen_range_int!(gen_range_i8, i8, -20i8, 100);
gen_range_int!(gen_range_i16, i16, -500i16, 2000);
gen_range_int!(gen_range_i32, i32, -200_000_000i32, 800_000_000);
gen_range_int!(gen_range_i64, i64, 3i64, 123_456_789_123);
gen_range_int!(gen_range_i128, i128, -12345678901234i128, 123_456_789_123_456_789);
// Algorithms such as Fisher–Yates shuffle often require uniform values from an
// incrementing range 0..n. We use -1..n here to prevent wrapping in the test
// from generating a 0-sized range.
gen_range_int!(gen_range_i8_low, i8, -1i8, 0);
gen_range_int!(gen_range_i16_low, i16, -1i16, 0);
gen_range_int!(gen_range_i32_low, i32, -1i32, 0);
gen_range_int!(gen_range_i64_low, i64, -1i64, 0);
gen_range_int!(gen_range_i128_low, i128, -1i128, 0);

// These were the initially tested ranges. They are likely to see fewer
// rejections than the low tests.
gen_range_int!(gen_range_i8_high, i8, -20i8, 100);
gen_range_int!(gen_range_i16_high, i16, -500i16, 2000);
gen_range_int!(gen_range_i32_high, i32, -200_000_000i32, 800_000_000);
gen_range_int!(gen_range_i64_high, i64, 3i64, 123_456_789_123);
gen_range_int!(gen_range_i128_high, i128, -12345678901234i128, 123_456_789_123_456_789);

// construct and sample from a floating-point range
macro_rules! gen_range_float {
Expand Down Expand Up @@ -239,3 +251,190 @@ macro_rules! gen_range_float {

gen_range_float!(gen_range_f32, f32, -20000.0f32, 100000.0);
gen_range_float!(gen_range_f64, f64, 123.456f64, 7890.12);


// In src/distributions/uniform.rs, we say:
// Implementation of [`uniform_single`] is optional, and is only useful when
// the implementation can be faster than `Self::new(low, high).sample(rng)`.

// `UniformSampler::uniform_single` compromises on the rejection range to be
// faster. This benchmark demonstrates both the speed gain of doing this, and
// the worst case behavior.

/// Sample random values from a pre-existing distribution. This uses the
/// half open `new` to be equivalent to the behavior of `uniform_single`.
macro_rules! uniform_sample {
($fnn:ident, $type:ident, $low:expr, $high:expr, $count:expr) => {
#[bench]
fn $fnn(b: &mut Bencher) {
let mut rng = Pcg64Mcg::from_entropy();
let low = black_box($low);
let high = black_box($high);
b.iter(|| {
for _ in 0..10 {
let dist = UniformInt::<$type>::new(low, high);
for _ in 0..$count {
black_box(dist.sample(&mut rng));
}
}
});
}
};
}

macro_rules! uniform_inclusive {
($fnn:ident, $type:ident, $low:expr, $high:expr, $count:expr) => {
#[bench]
fn $fnn(b: &mut Bencher) {
let mut rng = Pcg64Mcg::from_entropy();
let low = black_box($low);
let high = black_box($high);
b.iter(|| {
for _ in 0..10 {
let dist = UniformInt::<$type>::new_inclusive(low, high);
for _ in 0..$count {
black_box(dist.sample(&mut rng));
}
}
});
}
};
}

/// Use `uniform_single` to create a one-off random value
macro_rules! uniform_single {
($fnn:ident, $type:ident, $low:expr, $high:expr, $count:expr) => {
#[bench]
fn $fnn(b: &mut Bencher) {
let mut rng = Pcg64Mcg::from_entropy();
let low = black_box($low);
let high = black_box($high);
b.iter(|| {
for _ in 0..(10 * $count) {
black_box(UniformInt::<$type>::sample_single(low, high, &mut rng));
}
});
}
};
}


// Benchmark:
// n: can use the full generated range
// (n-1): only the max value is rejected: expect this to be fast
// n/2+1: almost half of the values are rejected, and we can do no better
// n/2: approximation rejects half the values but powers of 2 could have no rejection
// n/2-1: only a few values are rejected: expect this to be fast
// 6: approximation rejects 25% of values but could be faster. However modulo by
// low numbers is typically more expensive

// With the use of u32 as the minimum generated width, the worst-case u16 range
// (32769) will only reject 32769 / 4294967296 samples.
const HALF_16_BIT_UNSIGNED: u16 = 1 << 15;

uniform_sample!(uniform_u16x1_allm1_new, u16, 0, u16::max_value(), 1);
uniform_sample!(uniform_u16x1_halfp1_new, u16, 0, HALF_16_BIT_UNSIGNED + 1, 1);
uniform_sample!(uniform_u16x1_half_new, u16, 0, HALF_16_BIT_UNSIGNED, 1);
uniform_sample!(uniform_u16x1_halfm1_new, u16, 0, HALF_16_BIT_UNSIGNED - 1, 1);
uniform_sample!(uniform_u16x1_6_new, u16, 0, 6u16, 1);

uniform_single!(uniform_u16x1_allm1_single, u16, 0, u16::max_value(), 1);
uniform_single!(uniform_u16x1_halfp1_single, u16, 0, HALF_16_BIT_UNSIGNED + 1, 1);
uniform_single!(uniform_u16x1_half_single, u16, 0, HALF_16_BIT_UNSIGNED, 1);
uniform_single!(uniform_u16x1_halfm1_single, u16, 0, HALF_16_BIT_UNSIGNED - 1, 1);
uniform_single!(uniform_u16x1_6_single, u16, 0, 6u16, 1);

uniform_inclusive!(uniform_u16x10_all_new_inclusive, u16, 0, u16::max_value(), 10);
uniform_sample!(uniform_u16x10_allm1_new, u16, 0, u16::max_value(), 10);
uniform_sample!(uniform_u16x10_halfp1_new, u16, 0, HALF_16_BIT_UNSIGNED + 1, 10);
uniform_sample!(uniform_u16x10_half_new, u16, 0, HALF_16_BIT_UNSIGNED, 10);
uniform_sample!(uniform_u16x10_halfm1_new, u16, 0, HALF_16_BIT_UNSIGNED - 1, 10);
uniform_sample!(uniform_u16x10_6_new, u16, 0, 6u16, 10);

uniform_single!(uniform_u16x10_allm1_single, u16, 0, u16::max_value(), 10);
uniform_single!(uniform_u16x10_halfp1_single, u16, 0, HALF_16_BIT_UNSIGNED + 1, 10);
uniform_single!(uniform_u16x10_half_single, u16, 0, HALF_16_BIT_UNSIGNED, 10);
uniform_single!(uniform_u16x10_halfm1_single, u16, 0, HALF_16_BIT_UNSIGNED - 1, 10);
uniform_single!(uniform_u16x10_6_single, u16, 0, 6u16, 10);


const HALF_32_BIT_UNSIGNED: u32 = 1 << 31;

uniform_sample!(uniform_u32x1_allm1_new, u32, 0, u32::max_value(), 1);
uniform_sample!(uniform_u32x1_halfp1_new, u32, 0, HALF_32_BIT_UNSIGNED + 1, 1);
uniform_sample!(uniform_u32x1_half_new, u32, 0, HALF_32_BIT_UNSIGNED, 1);
uniform_sample!(uniform_u32x1_halfm1_new, u32, 0, HALF_32_BIT_UNSIGNED - 1, 1);
uniform_sample!(uniform_u32x1_6_new, u32, 0, 6u32, 1);

uniform_single!(uniform_u32x1_allm1_single, u32, 0, u32::max_value(), 1);
uniform_single!(uniform_u32x1_halfp1_single, u32, 0, HALF_32_BIT_UNSIGNED + 1, 1);
uniform_single!(uniform_u32x1_half_single, u32, 0, HALF_32_BIT_UNSIGNED, 1);
uniform_single!(uniform_u32x1_halfm1_single, u32, 0, HALF_32_BIT_UNSIGNED - 1, 1);
uniform_single!(uniform_u32x1_6_single, u32, 0, 6u32, 1);

uniform_inclusive!(uniform_u32x10_all_new_inclusive, u32, 0, u32::max_value(), 10);
uniform_sample!(uniform_u32x10_allm1_new, u32, 0, u32::max_value(), 10);
uniform_sample!(uniform_u32x10_halfp1_new, u32, 0, HALF_32_BIT_UNSIGNED + 1, 10);
uniform_sample!(uniform_u32x10_half_new, u32, 0, HALF_32_BIT_UNSIGNED, 10);
uniform_sample!(uniform_u32x10_halfm1_new, u32, 0, HALF_32_BIT_UNSIGNED - 1, 10);
uniform_sample!(uniform_u32x10_6_new, u32, 0, 6u32, 10);

uniform_single!(uniform_u32x10_allm1_single, u32, 0, u32::max_value(), 10);
uniform_single!(uniform_u32x10_halfp1_single, u32, 0, HALF_32_BIT_UNSIGNED + 1, 10);
uniform_single!(uniform_u32x10_half_single, u32, 0, HALF_32_BIT_UNSIGNED, 10);
uniform_single!(uniform_u32x10_halfm1_single, u32, 0, HALF_32_BIT_UNSIGNED - 1, 10);
uniform_single!(uniform_u32x10_6_single, u32, 0, 6u32, 10);

const HALF_64_BIT_UNSIGNED: u64 = 1 << 63;

uniform_sample!(uniform_u64x1_allm1_new, u64, 0, u64::max_value(), 1);
uniform_sample!(uniform_u64x1_halfp1_new, u64, 0, HALF_64_BIT_UNSIGNED + 1, 1);
uniform_sample!(uniform_u64x1_half_new, u64, 0, HALF_64_BIT_UNSIGNED, 1);
uniform_sample!(uniform_u64x1_halfm1_new, u64, 0, HALF_64_BIT_UNSIGNED - 1, 1);
uniform_sample!(uniform_u64x1_6_new, u64, 0, 6u64, 1);

uniform_single!(uniform_u64x1_allm1_single, u64, 0, u64::max_value(), 1);
uniform_single!(uniform_u64x1_halfp1_single, u64, 0, HALF_64_BIT_UNSIGNED + 1, 1);
uniform_single!(uniform_u64x1_half_single, u64, 0, HALF_64_BIT_UNSIGNED, 1);
uniform_single!(uniform_u64x1_halfm1_single, u64, 0, HALF_64_BIT_UNSIGNED - 1, 1);
uniform_single!(uniform_u64x1_6_single, u64, 0, 6u64, 1);

uniform_inclusive!(uniform_u64x10_all_new_inclusive, u64, 0, u64::max_value(), 10);
uniform_sample!(uniform_u64x10_allm1_new, u64, 0, u64::max_value(), 10);
uniform_sample!(uniform_u64x10_halfp1_new, u64, 0, HALF_64_BIT_UNSIGNED + 1, 10);
uniform_sample!(uniform_u64x10_half_new, u64, 0, HALF_64_BIT_UNSIGNED, 10);
uniform_sample!(uniform_u64x10_halfm1_new, u64, 0, HALF_64_BIT_UNSIGNED - 1, 10);
uniform_sample!(uniform_u64x10_6_new, u64, 0, 6u64, 10);

uniform_single!(uniform_u64x10_allm1_single, u64, 0, u64::max_value(), 10);
uniform_single!(uniform_u64x10_halfp1_single, u64, 0, HALF_64_BIT_UNSIGNED + 1, 10);
uniform_single!(uniform_u64x10_half_single, u64, 0, HALF_64_BIT_UNSIGNED, 10);
uniform_single!(uniform_u64x10_halfm1_single, u64, 0, HALF_64_BIT_UNSIGNED - 1, 10);
uniform_single!(uniform_u64x10_6_single, u64, 0, 6u64, 10);

const HALF_128_BIT_UNSIGNED: u128 = 1 << 127;

uniform_sample!(uniform_u128x1_allm1_new, u128, 0, u128::max_value(), 1);
uniform_sample!(uniform_u128x1_halfp1_new, u128, 0, HALF_128_BIT_UNSIGNED + 1, 1);
uniform_sample!(uniform_u128x1_half_new, u128, 0, HALF_128_BIT_UNSIGNED, 1);
uniform_sample!(uniform_u128x1_halfm1_new, u128, 0, HALF_128_BIT_UNSIGNED - 1, 1);
uniform_sample!(uniform_u128x1_6_new, u128, 0, 6u128, 1);

uniform_single!(uniform_u128x1_allm1_single, u128, 0, u128::max_value(), 1);
uniform_single!(uniform_u128x1_halfp1_single, u128, 0, HALF_128_BIT_UNSIGNED + 1, 1);
uniform_single!(uniform_u128x1_half_single, u128, 0, HALF_128_BIT_UNSIGNED, 1);
uniform_single!(uniform_u128x1_halfm1_single, u128, 0, HALF_128_BIT_UNSIGNED - 1, 1);
uniform_single!(uniform_u128x1_6_single, u128, 0, 6u128, 1);

uniform_inclusive!(uniform_u128x10_all_new_inclusive, u128, 0, u128::max_value(), 10);
uniform_sample!(uniform_u128x10_allm1_new, u128, 0, u128::max_value(), 10);
uniform_sample!(uniform_u128x10_halfp1_new, u128, 0, HALF_128_BIT_UNSIGNED + 1, 10);
uniform_sample!(uniform_u128x10_half_new, u128, 0, HALF_128_BIT_UNSIGNED, 10);
uniform_sample!(uniform_u128x10_halfm1_new, u128, 0, HALF_128_BIT_UNSIGNED - 1, 10);
uniform_sample!(uniform_u128x10_6_new, u128, 0, 6u128, 10);

uniform_single!(uniform_u128x10_allm1_single, u128, 0, u128::max_value(), 10);
uniform_single!(uniform_u128x10_halfp1_single, u128, 0, HALF_128_BIT_UNSIGNED + 1, 10);
uniform_single!(uniform_u128x10_half_single, u128, 0, HALF_128_BIT_UNSIGNED, 10);
uniform_single!(uniform_u128x10_halfm1_single, u128, 0, HALF_128_BIT_UNSIGNED - 1, 10);
uniform_single!(uniform_u128x10_6_single, u128, 0, 6u128, 10);

0 comments on commit c337164

Please sign in to comment.