Migrating from criterion

Step 1: Add zenbench alongside criterion

[dev-dependencies]
criterion = "0.8"                                          # keep
zenbench = { version = "0.1", features = ["criterion-compat"] }  # add

Step 2: Change one import per file

// Before:
use criterion::{criterion_group, criterion_main, Criterion, BenchmarkId, Throughput};

// After:
use zenbench::criterion_compat::*;
use zenbench::{criterion_group, criterion_main};

Zero code changes to your benchmark functions. Closures can borrow local data — no move or Clone needed.

Step 3: Run both

Both criterion and zenbench bench files coexist. Run each independently:

cargo bench --bench my_criterion_bench    # still works
cargo bench --bench my_zenbench_bench     # new

Step 4: Remove criterion when done

[dev-dependencies]
zenbench = "0.1"

What works unchanged

Everything in criterion's common API:

• criterion_group! / criterion_main!
• c.benchmark_group() / group.bench_function() / group.finish()
• c.bench_function() / c.bench_with_input()
• BenchmarkId::new() / BenchmarkId::from_parameter()
• Throughput::Bytes() / Throughput::Elements()
• b.iter() / b.iter_batched() / b.iter_batched_ref()
• group.sample_size() / group.measurement_time() / group.warm_up_time()
• black_box()

Incremental upgrades

Once migrated, add zenbench features one line at a time:

group.throughput_unit("pixels");       // custom unit: "Gpixels/s"
group.baseline("reference_impl");      // compare all vs this one
group.sort_by_speed();                 // fastest first in report
group.subgroup("SIMD variants");       // visual section headers

CLI flags work immediately:

cargo bench -- --save-baseline=main       # CI baselines
cargo bench -- --baseline=main            # regression gates
cargo bench -- --format=html              # browser report

Switching to the native API

When you want interleaved execution, the diff is small:

// criterion-compat (sequential):        // native (interleaved):
let mut g = c.benchmark_group("sort");   suite.group("sort", |g| {
g.bench_function("std", |b| ...);           g.bench("std", |b| ...);
g.bench_function("unstable", |b| ...);      g.bench("unstable", |b| ...);
g.finish();                              });

bench_function → bench, drop finish(), wrap in suite.group().

Comparison table