Cargo.toml

[package]
name = "quanta-stdlib-deviation"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
quanta = "0.12.1"
hdrhistogram = "7.5.4"

main.rs

use std::{thread, time::Duration, io::Write as _};

use hdrhistogram::Histogram;

const SLEEP_DUR: Duration = Duration::from_secs(1);

fn main() {
    const N: usize = 20;
    measure_elapsed("std", N, elapsed_std);
    measure_elapsed("quanta", N, elapsed_quanta);
}

fn measure_elapsed<F>(ty: &str, repeat: usize, f: F)
where
    F: Fn() -> Duration,
{
    let mut histo = Histogram::<u64>::new(5).unwrap();

    println!("running test for {ty}...");

    for _ in 1..=repeat {
        let elapsed = f();
        histo.record(elapsed.as_nanos() as u64).unwrap();

        print!(".");
        std::io::stdout().flush().unwrap();
    }

    println!(" done!\n");

    let min = histo.min();
    let p50 = histo.value_at_quantile(0.5);
    let p99 = histo.value_at_quantile(0.99);
    let max = histo.max();

    println!("{ty} statistics:");
    println!("  min: {min}ns\n  p50: {p50}ns\n  p99: {p99}ns\n  max: {max}ns");

    let range = max - min;
    let sleep_dur_ns = SLEEP_DUR.as_nanos() as u64;
    let lower_pct = (min as f64 / sleep_dur_ns as f64) * 100.0;
    let upper_pct = (max as f64 / sleep_dur_ns as f64) * 100.0;
    println!("  range: {range}ns ({lower_pct:.5}% to {upper_pct:.5}% of target)");
    println!("");
}

fn elapsed_std() -> Duration {
    let start = std::time::Instant::now();
    thread::sleep(SLEEP_DUR);
    start.elapsed()
}

fn elapsed_quanta() -> Duration {
    let start = quanta::Instant::now();
    thread::sleep(SLEEP_DUR);
    start.elapsed()
}