Add Criterion as dev-dependency, create a folder benches with benchmarks, here my_benchmarks.rs and comparison_benchmark.rs.
To get graphics with the benchmark results (in the generated html page), install gnuplot on your system.
Run cargo bench to run the benchmark.
The html report is generated in target/criterion/.
More details on Criterion can be found in the User Guide.
Regression testing can also be done by running cargo bench -- --save-baseline <name-of-baseline>, which will save the baseline results in baseline.json. Unfortunately, I did not get that to work yet.
cargo bench -- --save-baseline initial
Finished `bench` profile [optimized] target(s) in 0.10s
Running unittests src/lib.rs (target/release/deps/criterion_benchmark-c2076c60856bf728)
error: Unrecognized option: 'save-baseline'
error: bench failed, to rerun pass `--lib`
But next command does work:
cargo bench --bench my_benchmark -- --save-baseline inital
This will create a folder target/criterion/factorial 20/initial with json files that contain the benchmark results.
By passing --baseline <name-of-baseline> to next runs, they will be compared to this baseline.