cargo bench -- foo --exact
cargo-bench - Execute benchmarks of a package
cargo bench [OPTIONS] [BENCHNAME] [-- BENCH-OPTIONS]
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’re 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. 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 an
executable with a main function that 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.
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.
Compile, but don’t run benchmarks.
Run all benchmarks regardless of failure. Without this flag, Cargo will exit after the first executable fails. The Rust test harness will run all benchmarks within the executable to completion, this flag only applies to the executable as a whole.
By default, when no package selection options are given, the packages selected
depend on the selected manifest file (based on the current working directory if
--manifest-path is not given). If the manifest is the root of a workspace then
the workspaces default members are selected, otherwise only the package defined
by the manifest will be selected.
The default members of a workspace can be set explicitly with the
workspace.default-members key in the root manifest. If this is not set, a
virtual workspace will include all workspace members (equivalent to passing
--workspace), and a non-virtual workspace will include only the root crate itself.
Benchmark only the specified packages. See cargo-pkgid(1) for the SPEC format. This flag may be specified multiple times.
Benchmark all members in the workspace.
Deprecated alias for --workspace.
Exclude the specified packages. Must be used in conjunction with the
--workspace flag. This flag may be specified multiple times.
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. Setting targets to bench = false will stop
them from being benchmarked by default. Target selection options that take a
target by name ignore the bench flag and will always benchmark the given
target.
Passing target selection flags will benchmark only the specified targets.
Benchmark the package’s library.
Benchmark the specified binary. This flag may be specified multiple times.
Benchmark all binary targets.
Benchmark the specified example. This flag may be specified multiple times.
Benchmark all example targets.
Benchmark the specified integration test. This flag may be specified multiple times.
Benchmark all targets in test mode that have the test = true manifest
flag set. By default this includes the library and binaries built as
unittests, and integration tests. Be aware that this will also build any
required dependencies, so the lib target may be built twice (once as a
unittest, and once as a dependency for binaries, integration tests, etc.).
Targets may be enabled or disabled by setting the test flag in the
manifest settings for the target.
Benchmark the specified benchmark. This flag may be specified multiple times.
Benchmark all targets in benchmark mode that have the bench = true
manifest flag set. By default this includes the library and binaries built
as benchmarks, and bench targets. Be aware that this will also build any
required dependencies, so the lib target may be built twice (once as a
benchmark, and once as a dependency for binaries, benchmarks, etc.).
Targets may be enabled or disabled by setting the bench flag in the
manifest settings for the target.
Benchmark all targets. This is equivalent to specifying --lib --bins
--tests --benches --examples.
The feature flags allow you to control the enabled features for the "current"
package. The "current" package is the package in the current directory, or the
one specified in --manifest-path. If running in the root of a virtual
workspace, then the default features are selected for all workspace members,
or all features if --all-features is specified.
When no feature options are given, the default feature is activated for
every selected package.
Space or comma separated list of features to activate. These features only
apply to the current directory’s package. Features of direct dependencies
may be enabled with <dep-name>/<feature-name> syntax. This flag may be
specified multiple times, which enables all specified features.
Activate all available features of all selected packages.
Do not activate the default feature of the current directory’s
package.
Benchmark for the given architecture. The default is the host
architecture. The general format of the triple is
<arch><sub>-<vendor>-<sys>-<abi>. Run rustc --print target-list for a
list of supported targets.
This may also be specified with the build.target
config value.
Note that specifying this flag makes Cargo run in a different mode where the target artifacts are placed in a separate directory. See the build cache documentation for more details.
Directory for all generated artifacts and intermediate files. May also be
specified with the CARGO_TARGET_DIR environment variable, or the
build.target-dir config value. Defaults
to target in the root of the workspace.
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
Use verbose output. May be specified twice for "very verbose" output which
includes extra output such as dependency warnings and build script output.
May also be specified with the term.verbose
config value.
No output printed to stdout.
Control when colored output is used. Valid values:
auto (default): Automatically detect if color support is available on the
terminal.
always: Always display colors.
never: Never display colors.
May also be specified with the term.color
config value.
The output format for diagnostic messages. Can be specified multiple times and consists of comma-separated values. Valid values:
human (default): Display in a human-readable text format.
short: Emit shorter, human-readable text messages.
json: Emit JSON messages to stdout. See
the reference
for more details.
json-diagnostic-short: Ensure the rendered field of JSON messages contains
the "short" rendering from rustc.
json-diagnostic-rendered-ansi: Ensure the rendered field of JSON messages
contains embedded ANSI color codes for respecting rustc’s default color
scheme.
json-render-diagnostics: Instruct Cargo to not include rustc diagnostics in
in JSON messages printed, but instead Cargo itself should render the
JSON diagnostics coming from rustc. Cargo’s own JSON diagnostics and others
coming from rustc are still emitted.
Path to the Cargo.toml file. By default, Cargo searches for the
Cargo.toml file in the current directory or any parent directory.
Either of these flags requires that the Cargo.lock file is
up-to-date. If the lock file is missing, or it needs to be updated, Cargo will
exit with an error. The --frozen flag also prevents Cargo from
attempting to access the network to determine if it is out-of-date.
These may be used in environments where you want to assert that the
Cargo.lock file is up-to-date (such as a CI build) or want to avoid network
access.
Prevents Cargo from accessing the network for any reason. Without this flag, Cargo will stop with an error if it needs to access the network and the network is not available. With this flag, Cargo will attempt to proceed without the network if possible.
Beware that this may result in different dependency resolution than online mode. Cargo will restrict itself to crates that are downloaded locally, even if there might be a newer version as indicated in the local copy of the index. See the cargo-fetch(1) command to download dependencies before going offline.
May also be specified with the net.offline config value.
If Cargo has been installed with rustup, and the first argument to cargo
begins with +, it will be interpreted as a rustup toolchain name (such
as +stable or +nightly).
See the rustup documentation
for more information about how toolchain overrides work.
Prints help information.
Unstable (nightly-only) flags to Cargo. Run cargo -Z help for
details.
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.
Number of parallel jobs to run. May also be specified with the
build.jobs config value. Defaults to
the number of CPUs.
Profiles may be used to configure compiler options such as optimization levels and debug settings. See the reference for more details.
Benchmarks are always built with the bench profile. Binary and lib targets
are built separately as benchmarks with the bench profile. Library targets
are built with the release profiles when linked to binaries and benchmarks.
Dependencies use the release profile.
If you need a debug build of a benchmark, try building it with
cargo-build(1) which will use the test profile which is by default
unoptimized and includes debug information. You can then run the debug-enabled
benchmark manually.
See the reference for details on environment variables that Cargo reads.
Cargo succeeded.
Cargo failed to complete.
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