How to benchmark memory usage of a function?

Question

I notice that Rust\'s test has a benchmark mode that will measure execution time in ns/iter, but I could not find a way to measure memory usage.

How wou

Answer 1

Now there is jemalloc_ctl crate which provides convenient safe typed API. Add it to your Cargo.toml:

[dependencies]
jemalloc-ctl = "0.3"
jemallocator = "0.3"

Then configure jemalloc to be global allocator and use methods from jemalloc_ctl::stats module:

• jemalloc_ctl::stats::allocated
• jemalloc_ctl::stats::resident

---

Here is official example:

use std::thread;
use std::time::Duration;
use jemalloc_ctl::{stats, epoch};

#[global_allocator]
static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;

fn main() {
    loop {
        // many statistics are cached and only updated when the epoch is advanced.
        epoch::advance().unwrap();

        let allocated = stats::allocated::read().unwrap();
        let resident = stats::resident::read().unwrap();
        println!("{} bytes allocated/{} bytes resident", allocated, resident);
        thread::sleep(Duration::from_secs(10));
    }
}