cargo bench用于在代码中以#{bench]标识（代码目录下有benches文件夹），类似于测试用例#[test]标识（代码目录下有tests文件夹）
支持的子命令如下：
# cargo bench --help
cargo-bench
Execute all benchmarks of a local package
USAGE:
cargo bench [OPTIONS] [BENCHNAME] [-- ...]
OPTIONS:
-q, --quiet No output printed to stdout
--lib Benchmark only this package's library
--bin ... Benchmark only the specified binary
--bins Benchmark all binaries
--example ... Benchmark only the specified example
--examples Benchmark all examples
--test ... Benchmark only the specified test target
--tests Benchmark all tests
--bench ... Benchmark only the specified bench target
--benches Benchmark all benches
--all-targets Benchmark all targets
--no-run Compile, but don't run benchmarks
-p, --package ... Package to run benchmarks for
--all Benchmark all packages in the workspace
--exclude ... Exclude packages from the benchmark
-j, --jobs Number of parallel jobs, defaults to # of CPUs
--features Space-separated list of features to activate
--all-features Activate all available features
--no-default-features Do not activate the `default` feature
--target Build for the target triple
--target-dir Directory for all generated artifacts
--manifest-path Path to Cargo.toml
--message-format Error format [default: human] [possible values: human, json, short]
--no-fail-fast Run all benchmarks regardless of failure
-v, --verbose Use verbose output (-vv very verbose/build.rs output)
--color Coloring: auto, always, never
--frozen Require Cargo.lock and cache are up to date
--locked Require Cargo.lock is up to date
-Z ... Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details
-h, --help Prints help information
ARGS:
If specified, only run benches containing this string in their names
... Arguments for the bench binary
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`.
If the `--package` argument is given, then SPEC is a package ID specification
which indicates which package should be benchmarked. If it is not given, then
the current package is benchmarked. For more information on SPEC and its format,
see the `cargo help pkgid` command.
All packages in the workspace are benchmarked if the `--all` flag is supplied. The
`--all` flag is automatically assumed for a virtual manifest.
Note that `--exclude` has to be specified in conjunction with the `--all` flag.
The `--jobs` argument affects the building of the benchmark executable but does
not affect how many jobs are used when running the benchmarks.
Compilation can be customized with the `bench` profile in the manifest.
