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use crate::stats::{winsorize, Summary};
use std::cmp::max;
use std::hint::black_box;
use std::time::{Duration, Instant};
pub struct Bencher {
summary: Option<Summary>,
pub bytes: u64,
}
impl Bencher {
pub(crate) fn new() -> Self {
Self {
summary: None,
bytes: 0,
}
}
/// Callback for benchmark functions to run in their body.
pub fn iter<T, F>(&mut self, mut inner: F)
where
F: FnMut() -> T,
{
self.summary = Some(iter(&mut inner));
}
pub(crate) fn summary(&self) -> Option<Summary> {
self.summary
}
}
#[cfg(feature = "tokio")]
pub struct AsyncBencher {
summary: Option<Summary>,
pub bytes: u64,
}
#[cfg(feature = "tokio")]
impl AsyncBencher {
pub(crate) fn new() -> Self {
Self {
summary: None,
bytes: 0,
}
}
/// Callback for benchmark functions to run in their body.
pub async fn iter<T, F>(&mut self, mut inner: F)
where
F: FnMut() -> std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send>>
+ Send
+ Sync
+ 'static,
{
self.summary = Some(async_iter(&mut inner).await);
}
pub(crate) fn summary(&self) -> Option<Summary> {
self.summary
}
}
fn ns_iter_inner<T, F>(inner: &mut F, k: u64) -> u64
where
F: FnMut() -> T,
{
let start = Instant::now();
for _ in 0..k {
black_box(inner());
}
start.elapsed().as_nanos() as u64
}
#[cfg(feature = "tokio")]
async fn async_ns_iter_inner<T, F>(inner: &mut F, k: u64) -> u64
where
F: FnMut() -> std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send>>
+ Send
+ Sync
+ 'static,
{
let start = tokio::time::Instant::now();
for _ in 0..k {
black_box(inner().await);
}
start.elapsed().as_nanos() as u64
}
// From https://github.com/rust-lang/rust/blob/master/library/test/src/bench.rs
pub fn iter<T, F>(inner: &mut F) -> Summary
where
F: FnMut() -> T,
{
// Initial bench run to get ballpark figure.
let ns_single = ns_iter_inner(inner, 1);
// Try to estimate iter count for 1ms falling back to 1m
// iterations if first run took < 1ns.
let ns_target_total = 1_000_000; // 1ms
let mut n = ns_target_total / max(1, ns_single);
// if the first run took more than 1ms we don't want to just
// be left doing 0 iterations on every loop. The unfortunate
// side effect of not being able to do as many runs is
// automatically handled by the statistical analysis below
// (i.e., larger error bars).
n = max(1, n);
let mut total_run = Duration::new(0, 0);
let samples: &mut [f64] = &mut [0.0_f64; 50];
loop {
let loop_start = Instant::now();
for p in &mut *samples {
*p = ns_iter_inner(inner, n) as f64 / n as f64;
}
winsorize(samples, 5.0);
let summ = Summary::new(samples);
for p in &mut *samples {
let ns = ns_iter_inner(inner, 5 * n);
*p = ns as f64 / (5 * n) as f64;
}
winsorize(samples, 5.0);
let summ5 = Summary::new(samples);
let loop_run = loop_start.elapsed();
// If we've run for 100ms and seem to have converged to a
// stable median.
if loop_run > Duration::from_millis(100)
&& summ.median_abs_dev_pct < 1.0
&& summ.median - summ5.median < summ5.median_abs_dev
{
return summ5;
}
total_run += loop_run;
// Longest we ever run for is 3s.
if total_run > Duration::from_secs(3) {
return summ5;
}
// If we overflow here just return the results so far. We check a
// multiplier of 10 because we're about to multiply by 2 and the
// next iteration of the loop will also multiply by 5 (to calculate
// the summ5 result)
n = match n.checked_mul(10) {
Some(_) => n * 2,
None => {
return summ5;
}
};
}
}
#[cfg(feature = "tokio")]
pub async fn async_iter<T, F>(inner: &mut F) -> Summary
where
F: FnMut() -> std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send>>
+ Send
+ Sync
+ 'static,
{
// Initial bench run to get ballpark figure.
let ns_single = async_ns_iter_inner(inner, 1).await;
// Try to estimate iter count for 1ms falling back to 1m
// iterations if first run took < 1ns.
let ns_target_total = 1_000_000; // 1ms
let mut n = ns_target_total / max(1, ns_single);
// if the first run took more than 1ms we don't want to just
// be left doing 0 iterations on every loop. The unfortunate
// side effect of not being able to do as many runs is
// automatically handled by the statistical analysis below
// (i.e., larger error bars).
n = max(1, n);
let mut total_run = Duration::new(0, 0);
let samples: &mut [f64] = &mut [0.0_f64; 50];
loop {
let loop_start = tokio::time::Instant::now();
for p in &mut *samples {
*p = async_ns_iter_inner(inner, n).await as f64 / n as f64;
}
winsorize(samples, 5.0);
let summ = Summary::new(samples);
for p in &mut *samples {
let ns = async_ns_iter_inner(inner, 5 * n).await;
*p = ns as f64 / (5 * n) as f64;
}
winsorize(samples, 5.0);
let summ5 = Summary::new(samples);
let loop_run = loop_start.elapsed();
// If we've run for 100ms and seem to have converged to a
// stable median.
if loop_run > Duration::from_millis(100)
&& summ.median_abs_dev_pct < 1.0
&& summ.median - summ5.median < summ5.median_abs_dev
{
return summ5;
}
total_run += loop_run;
// Longest we ever run for is 3s.
if total_run > Duration::from_secs(3) {
return summ5;
}
// If we overflow here just return the results so far. We check a
// multiplier of 10 because we're about to multiply by 2 and the
// next iteration of the loop will also multiply by 5 (to calculate
// the summ5 result)
n = match n.checked_mul(10) {
Some(_) => n * 2,
None => {
return summ5;
}
};
}
}