alloc_tracker 0.7.10

Memory allocation tracking utilities for benchmarks and performance analysis.

This package provides utilities to track memory allocations during code execution, enabling analysis of allocation patterns in benchmarks and performance tests. It reports bytes allocated per iteration, allocations per iteration, and the peak amount of memory one iteration holds at a single moment.

Basic usage

The typical pattern is to drive measurement from Criterion's iter_custom function, feeding its chosen iteration count into iterations so each recorded span covers a whole sample rather than a single iteration:

use std::hint::black_box;
use std::time::Instant;

use alloc_tracker::{Allocator, Session};
use criterion::Criterion;

#[global_allocator]
static ALLOCATOR: Allocator<std::alloc::System> = Allocator::system();

fn bench(c: &mut Criterion) {
    let session = Session::new();

    let operation = session.operation("my_operation");
    c.bench_function("my_operation", |b| {
        b.iter_custom(|iters| {
            let start = Instant::now();
            let _span = operation.measure_thread().iterations(iters);

            for _ in 0..iters {
                black_box(vec![1, 2, 3, 4, 5]);
            }

            start.elapsed()
        });
    });

    // When `session` is dropped it prints a human-readable summary to stdout and
    // writes machine-readable JSON files (one per operation) into the Cargo
    // target directory: target/alloc_tracker/<operation>.json.
}

You do not need to specify the iteration count up front, as long as it is provided before the span is dropped. This allows you to measure work whose extent is not known at the start.

measure_thread observes only the calling thread and is the right choice whenever the measured work stays on that thread. It also covers work spread across threads that you can instrument, provided each worker counts iterations of its own: an operation combines its spans as repeated samples of one per-iteration cost rather than adding them up. Use measure_process when the work is performed by threads you cannot instrument, or when several threads collaborate on every iteration, accepting that it also picks up allocations from unrelated threads, that its totals are approximate, and that it withholds peak memory from the whole operation.

alloc_tracker 0.7.10

Basic usage

See also