Macro iai_callgrind::main

macro_rules! main {
    ( callgrind_args = $( $args:literal ),* $(,)*; functions = $( $func_name:ident ),+ $(,)* ) => { ... };
    ( $( $func_name:ident ),+ $(,)* ) => { ... };
}

Macro which expands to a benchmark harness.

This macro has two forms:

main!(func1, func2)

or

main!(
    callgrind_args = "--arg-with-flags=yes", "arg-without-flags=is_ok_too"
    functions = func1, func2
)

Using Iai-callgrind requires disabling the benchmark harness generated automatically by rustc. This can be done like so:

[[bench]]
name = "my_bench"
harness = false

To be able to run any iai-callgrind benchmarks, you’ll also need the iai-callgrind-runner installed with the binary somewhere in your $PATH for example with

cargo install iai-callgrind-runner

my_bench must be a rust file inside the ‘benches’ directory, like so:

benches/my_bench.rs

Since we’ve disabled the default benchmark harness, we need to add our own:

use iai_callgrind::main;

// `#[inline(never)]` is important! Without it there won't be any metrics
#[inline(never)]
fn bench_method1() {
}

#[inline(never)]
fn bench_method2() {
}

main!(bench_method1, bench_method2);

The iai_callgrind::main macro expands to a main function which runs all of the benchmarks.