5.5 KiB
cargo-bench(1)
{{~*set command="bench"}} {{~*set actionverb="Benchmark"}} {{~*set nouns="benchmarks"}} {{~*set multitarget=true}}
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.
Working directory of benchmarks
The working directory of every benchmark is set to the root directory of the
package the benchmark belongs to.
Setting the working directory of benchmarks to the package's root directory
makes it possible for benchmarks to reliably access the package's files using
relative paths, regardless from where cargo bench
was executed from.
OPTIONS
Benchmark Options
{{> options-test }}
{{> section-package-selection }}
Target Selection
When no target selection options are given, cargo bench
will build the
following targets of the selected packages:
- lib --- used to link with binaries and benchmarks
- bins (only if benchmark targets are built and required features are available)
- lib as a benchmark
- bins as benchmarks
- benchmark targets
The default behavior can be changed by setting the bench
flag for the target
in the manifest settings. Setting examples to bench = true
will build and
run the example as a benchmark, replacing the example's main
function with
the libtest harness.
Setting targets to bench = false
will stop them from being bencharmked by
default. Target selection options that take a target by name (such as
--example foo
) ignore the bench
flag and will always benchmark the given
target.
See Configuring a target for more information on per-target settings.
{{> options-targets-bin-auto-built }}
{{> options-targets }}
{{> section-features }}
Compilation Options
{{#options}}
{{> options-target-triple }}
{{> options-profile }}
{{> options-timings }}
{{/options}}
Output Options
{{#options}} {{> options-target-dir }} {{/options}}
Display Options
By default the Rust test harness hides output from benchmark execution to keep
results readable. Benchmark output can be recovered (e.g., for debugging) by
passing --nocapture
to the benchmark binaries:
cargo bench -- --nocapture
{{#options}}
{{> options-display }}
{{> options-message-format }}
{{/options}}
Manifest Options
{{#options}} {{> options-manifest-path }}
{{> options-ignore-rust-version }}
{{> options-locked }} {{/options}}
{{> section-options-common }}
Miscellaneous Options
The --jobs
argument affects the building of the benchmark executable but
does not affect how many threads are used when running the benchmarks. The
Rust test harness runs benchmarks serially in a single thread.
{{#options}} {{> options-jobs }} {{/options}}
While cargo bench
involves compilation, it does not provide a --keep-going
flag. Use --no-fail-fast
to run as many benchmarks as possible without
stopping at the first failure. To "compile" as many benchmarks as possible, use
--benches
to build benchmark binaries separately. For example:
cargo build --benches --release --keep-going
cargo bench --no-fail-fast
{{> section-environment }}
{{> section-exit-status }}
EXAMPLES
-
Build and execute all the benchmarks of the current package:
cargo bench
-
Run only a specific benchmark within a specific benchmark target:
cargo bench --bench bench_name -- modname::some_benchmark
SEE ALSO
{{man "cargo" 1}}, {{man "cargo-test" 1}}