huwb / rust-simple-stopwatch

Minimal stopwatch for rust. Returns floats.

rust-simple-stopwatch

What is it?

A minimal no-thrills stopwatch. Returns time values as 32bit floats. Uses time::precise_time_ns under the hood.

Setup

Add the dependency simple-stopwatch to your Cargo.toml file, for example:

[dependencies]
simple-stopwatch="0.1.4"

Then import the stopwatch anywhere you would like to use it:

extern crate simple_stopwatch;
use simple_stopwatch::Stopwatch;

Example Use

There is minimal state in simple-stopwatch and it is essentially always running. Upon creation it grabs a timestamp, after which it will report elapsed time from its member functions.

fn my_function() {
  let sw = Stopwatch::start_new();
  
  do_some_heavy_work();
  
  let elapsed_ms = sw.ms();
  println!("Time taken: {}ms", elapsed_ms);
}

The restart method updates the stored timestamp to the current time.

Performance Thoughts

The code make use of a small amount of code from the time crate, which uses a system call to obtain a high precision time stamp. The overhead of this call appears to be very small from my experiments so far - on my modest system I measure 100,000 calls taking 2.8ms.

However I would exercise caution leaving this stopwatch code active in high-performance release code. It is not yet well-tested on a range of operating systems and hardware, so it would be worth comparing carefully with the code compiled in vs out to see what mileage you get!

Inspiration / Other Projects

• stopwatch by Chucky Ellison