time_this 0.2.1

two macros to quickly time functions for debugging purposes
Documentation

A proc macro and a macro attribute to quickly time functions. Uses std::time::Instant so relies on std to work.

#[time_this]

This macro can be used to time any function you want using std::time::Instant. It may not work correctly with async fn and it definitely doesn't work with const fn, even if called in a non-const context. If needed, you can write a small wrapping fn if you need to time a const fn. It will print:

  • the time in ns if the function took less than 1μs.
  • the time in μs if the function took less than 1ms.
  • the time in ms if the function took longer than 1ms, but less than 1s.
  • the time in s if the function took more than a second, with two decimal digits.
use time_this::time_this;

#[time_this]
fn add(a: u32, b: u32) -> u32 {
    a + b
}

fn main() {
    let result = add(3, 5);
    // function 'add()' took 37ns
}

time!()

This macro can be used to time any expression you want using std::time::Instant. It returns the result of the expression, similar to dbg!(). It may not work correctly with async fn. Instead of printing the function name, it will print the file/line the expression that was timed at.

use time_this::time;

fn add(a: u32, b: u32) -> u32 {
    a + b
}

fn main() {
    let result = time!(add(3, 5));
    // expression at [tests/tests.rs:33] took 28ns
}