microbench

A micro-benchmarking library (inspired by core_bench).

Released under the Apache License 2.0.

Supported on Rust 1.31.0 and later.

Note: The retain function (used to prevent the optimizer from removing computations) may not operate correctly or may have poor performance on the stable and beta channels of Rust. If you are using a nightly release of Rust, enable the nightly crate feature to enable a better implementation of this function.

Overview

microbench uses linear regression to estimate the execution time of code segments. For example, the following table might represent data collected by microbench about a code segment.

microbench of course takes many more than 5 samples and the number of iterations grows geometrically rather than linearly, but the idea remains the same. After collecting data like this, microbench uses ordinary least squares (OLS) linear regression to estimate the actual execution time of the code segment. Using OLS with the above data would yield an estimated execution time of 9.6 nanoseconds with a goodness of fit (R²) of 0.992.

Example

use microbench::{self, Options};

fn fibonacci_iterative(n: u64) -> u64 {
    let (mut x, mut y, mut z) = (0, 1, 1);
    for _ in 0..n { x = y; y = z; z = x + y; }
    x
}

fn fibonacci_recursive(n: u64) -> u64 {
    if n < 2 {
        n
    } else {
        fibonacci_recursive(n - 2) + fibonacci_recursive(n - 1)
    }
}

let options = Options::default();
microbench::bench(&options, "iterative_16", || fibonacci_iterative(16));
microbench::bench(&options, "recursive_16", || fibonacci_recursive(16));

Example output:

iterative_16 (5.0s) ...                  281.733 ns/iter (0.998 R²)
recursive_16 (5.0s) ...                9_407.020 ns/iter (0.997 R²)