Rust bench helper

bench.rs

pub fn bench_point(identifier: &str) {
    BENCH_POINTS.lock().unwrap().push(BenchPoint {
        identifier: identifier.to_string(),
        time: Utc::now(),
    })
}

pub static BENCH_POINTS: Mutex<Vec<BenchPoint>> = Mutex::new(Vec::new());

// ideally this would be a macro to capture file and location
pub fn bench_point(identifier: &str) {
    BENCH_POINTS.lock().unwrap().push(BenchPoint {
        identifier: identifier.to_string(),
        time: Utc::now(),
    })
}

pub fn bench_clear(identifier: &str) {
    BENCH_POINTS.lock().unwrap().push(BenchPoint {
        identifier: identifier.to_string(),
        time: Utc::now(),
    })
}

pub fn bench_results() {
    let mut bench_points = BENCH_POINTS.lock().unwrap();
    bench_points.sort_by(|a, b| a.time.cmp(&b.time));

    let Some(start_time) = bench_points.first() else {
        return;
    };

    let mut previous_time = start_time.time;

    for BenchPoint { identifier, time } in bench_points.iter() {
        let diff_from_start = *time - start_time.time;
        let diff_from_previous = *time - previous_time;
        println!("{identifier: <30}\t{diff_from_start: <10}\t{diff_from_previous: <10}");
        previous_time = *time;
    }
}

To use:

fn do_it() {
    bench_point("step 1 start")
    // do some work step 1
    bench_point("step 1 stop")

    bench_point("step 2 start")
    // do some work step 2
    bench_point("step 2 stop")

    bench_result()
}

There is soo much more that can be improved, but was sufficient for quick use case I had.

Improvements:

• optimise api (can be step based ? and can create instance of bench for a method)
• can clear bench points
• clear
• use macro (can record line numbers and file, and this can lead to hint display in vs code of actual result times, and maybe don't need to specify identifier at this stage)
• toggle bench on and off
• time diffs to be easier to read

Tangential RND topic: flame graph might be kewl https://github.com/flamegraph-rs/flamegraph