cargo-bench

cargo-bench(1)

NAME

cargo-bench --- Execute benchmarks of a package

SYNOPSIS

cargo bench [options] [benchname] [-- bench-options]

DESCRIPTION

Compile and execute benchmarks.

The benchmark filtering argument benchname and all the arguments following the two dashes (--) are passed to the benchmark binaries and thus to libtest (rustc's built in unit-test and micro-benchmarking framework). If you are passing arguments to both Cargo and the binary, the ones after -- go to the binary, the ones before go to Cargo. For details about libtest's arguments see the output of cargo bench -- --help and check out the rustc book's chapter on how tests work at https://doc.rust-lang.org/rustc/tests/index.html.

As an example, this will run only the benchmark named foo (and skip other similarly named benchmarks like foobar):

cargo bench -- foo --exact

Benchmarks are built with the --test option to rustc which creates a special executable by linking your code with libtest. The executable automatically runs all functions annotated with the #[bench] attribute. Cargo passes the --bench flag to the test harness to tell it to run only benchmarks, regardless of whether the harness is libtest or a custom harness.

The libtest harness may be disabled by setting harness = false in the target manifest settings, in which case your code will need to provide its own main function to handle running benchmarks.

Note: The #[bench] attribute is currently unstable and only available on the nightly channel. There are some packages available on crates.io that may help with running benchmarks on the stable channel, such as Criterion.

By default, cargo bench uses the [bench profile], which enables optimizations and disables debugging information. If you need to debug a benchmark, you can use the --profile=dev command-line option to switch to the dev profile. You can then run the debug-enabled benchmark within a debugger.