Precise timing about Instant

1 
use std::time::{Instant, Duration};
use std::thread;

fn main() {
    let instant = Instant::now();

    thread::sleep(Duration::from_secs(1));
    println!("{}", instant.elapsed().as_nanos());
}

# cargo run --release 
C:\Users\Administrator\CLionProjects\testy>cargo run --release
    Finished release [optimized] target(s) in 0.00s
     Running `target\release\testy.exe`
1015759000

how can i precise timing? the result is not what I want.

2

That is the precise timing. thread::sleep isn't guaranteed to be precise so that's where the fluctuations come from

1 Like
3

It's up to the OS scheduler how long the sleep actually lasts:

The thread may sleep longer than the duration specified due to scheduling specifics or platform-dependent functionality. It will never sleep less.

You can increase the timer resolution via some Windows API calls (not sure how you'd do the equivalent for other platforms), but sleeping will never be 100% precise.

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4

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