Benchmarking programs in Rust

Question

How is it possible to benchmark programs in Rust? For example, how would I get execution time of program in seconds?

Answer 1

This answer is outdated! The time crate does not offer any advantages over std::time in regards to benchmarking. Please see the answers below for up to date information.

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You might try timing individual components within the program using the time crate.

Answer 2

If you simply want to time a piece of code, you can use the time crate. time meanwhile deprecated, though. A follow-up crate is chrono.

Add time = "*" to your Cargo.toml.

Add

extern crate time;
use time::PreciseTime;

before your main function and

let start = PreciseTime::now();
// whatever you want to do
let end = PreciseTime::now();
println!("{} seconds for whatever you did.", start.to(end));

Complete example

Cargo.toml

[package]
name = "hello_world" # the name of the package
version = "0.0.1"    # the current version, obeying semver
authors = [ "you@example.com" ]
[[bin]]
name = "rust"
path = "rust.rs"
[dependencies]
rand = "*" # Or a specific version
time = "*"

rust.rs

extern crate rand;
extern crate time;

use rand::Rng;
use time::PreciseTime;

fn main() {
    // Creates an array of 10000000 random integers in the range 0 - 1000000000
    //let mut array: [i32; 10000000] = [0; 10000000];
    let n = 10000000;
    let mut array = Vec::new();

    // Fill the array
    let mut rng = rand::thread_rng();
    for _ in 0..n {
        //array[i] = rng.gen::<i32>();
        array.push(rng.gen::<i32>());
    }

    // Sort
    let start = PreciseTime::now();
    array.sort();
    let end = PreciseTime::now();

    println!("{} seconds for sorting {} integers.", start.to(end), n);
}