cargo bench
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’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.
OPTIONS
Benchmark Options
- --no-run
-
Compile, but don’t run benchmarks.
- --no-fail-fast
-
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.
Package Selection
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.
- -p SPEC…
- --package SPEC…
-
Benchmark only the specified packages. See cargo-pkgid(1) for the SPEC format. This flag may be specified multiple times.
- --all
-
Benchmark all members in the workspace.
- --exclude SPEC…
-
Exclude the specified packages. Must be used in conjunction with the
--allflag. This flag may be specified multiple times.
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. 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.
- --lib
-
Benchmark the package’s library.
- --bin NAME…
-
Benchmark the specified binary. This flag may be specified multiple times.
- --bins
-
Benchmark all binary targets.
- --example NAME…
-
Benchmark the specified example. This flag may be specified multiple times.
- --examples
-
Benchmark all example targets.
- --test NAME…
-
Benchmark the specified integration test. This flag may be specified multiple times.
- --tests
-
Benchmark all targets in test mode that have the
test = truemanifest 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 thetestflag in the manifest settings for the target. - --bench NAME…
-
Benchmark the specified benchmark. This flag may be specified multiple times.
- --benches
-
Benchmark all targets in benchmark mode that have the
bench = truemanifest 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 thebenchflag in the manifest settings for the target. - --all-targets
-
Benchmark all targets. This is equivalent to specifying
--lib --bins --tests --benches --examples.
Feature Selection
When no feature options are given, the default feature is activated for
every selected package.
- --features FEATURES
-
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. - --all-features
-
Activate all available features of all selected packages.
- --no-default-features
-
Do not activate the
defaultfeature of the current directory’s package.
Compilation Options
- --target TRIPLE
-
Benchmark for the given architecture. The default is the host architecture. The general format of the triple is
<arch><sub>-<vendor>-<sys>-<abi>. Runrustc --print target-listfor a list of supported targets.This may also be specified with the
build.targetconfig value.
Output Options
- --target-dir DIRECTORY
-
Directory for all generated artifacts and intermediate files. May also be specified with the
CARGO_TARGET_DIRenvironment variable, or thebuild.target-dirconfig value. Defaults totargetin the root of the workspace.
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
- -v
- --verbose
-
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.verboseconfig value. - -q
- --quiet
-
No output printed to stdout.
- --color WHEN
-
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.colorconfig value. -
- --message-format FMT
-
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.
-
Manifest Options
- --manifest-path PATH
-
Path to the
Cargo.tomlfile. By default, Cargo searches in the current directory or any parent directory for theCargo.tomlfile. - --frozen
- --locked
-
Either of these flags requires that the
Cargo.lockfile is up-to-date. If the lock file is missing, or it needs to be updated, Cargo will exit with an error. The--frozenflag 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.lockfile is up-to-date (such as a CI build) or want to avoid network access. - --offline
-
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.offlineconfig value.
Common Options
- -h
- --help
-
Prints help information.
- -Z FLAG…
-
Unstable (nightly-only) flags to Cargo. Run
cargo -Z helpfor details.
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.
- -j N
- --jobs N
-
Number of parallel jobs to run. May also be specified with the
build.jobsconfig value. Defaults to the number of CPUs.
PROFILES
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.
ENVIRONMENT
See the reference for details on environment variables that Cargo reads.
Exit Status
- 0
-
Cargo succeeded.
- 101
-
Cargo failed to complete.
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