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.
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 current working directory. In the root of a virtual workspace,
all workspace members are selected (--all is implied). Otherwise, only the
package in the current directory will be selected. The default packages may be
overridden with the workspace.default-members key in the root Cargo.toml
manifest.
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.
Exclude the specified packages. Must be used in conjunction with the
--all 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.
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.
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.
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. Valid values:
human (default): Display in a human-readable text format.
json: Emit JSON messages to stdout.
short: Emit shorter, human-readable text messages.
Path to the Cargo.toml file. By default, Cargo searches in the current
directory or any parent directory for the Cargo.toml file.
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.
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