add benches

Cargo.toml

@@ -20,6 +20,7 @@ sha3 = "0.10.6"
 structopt = { version = "0.3.26", default-features = false }
 env_logger = "0.11.5"
 thiserror = "1.0.63"
+criterion = "0.3"
 
 [dev-dependencies]
 debug_print = { version = "1.0.0" }
@@ -34,3 +35,8 @@ plonky2_crypto = { git = "https://github.com/Lagrange-Labs/plonky2-crypto", bran
 
 [profile.dev]
 opt-level = 3
+
+[[bench]]
+name = "hash_chain_bench"
+path = "benches/hash_chain_benches.rs"
+harness = false  # Disable the default test harness for benchmarks

benches/hash_chain_benches.rs

@@ -0,0 +1,39 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use hash_chain::HashChain;
+use plonky2::{
+    field::goldilocks_field::GoldilocksField,
+    plonk::{
+        circuit_builder::CircuitBuilder,
+        circuit_data::CircuitConfig,
+        config::{GenericConfig, PoseidonGoldilocksConfig},
+    },
+};
+
+fn hash_chain_benchmark(c: &mut Criterion) {
+    const D: usize = 2;
+    type C = PoseidonGoldilocksConfig;
+    type F = <C as GenericConfig<D>>::F;
+
+    let config = CircuitConfig::standard_recursion_config();
+
+    let step_sizes = [2, 4, 8, 16, 32, 64]; // Example step sizes
+
+    for &steps in &step_sizes {
+        c.bench_function(&format!("hash_chain_{}_steps", steps), |b| {
+            b.iter(|| {
+                // Create the circuit inside the black_box to ensure it is evaluated
+                let mut circuit = black_box(CircuitBuilder::<F, D>::new(config.clone()));
+
+                let (_, _) = <CircuitBuilder<GoldilocksField, D> as HashChain<
+                    GoldilocksField,
+                    D,
+                    C,
+                >>::build_hash_chain_circuit(&mut circuit, steps)
+                .unwrap();
+            });
+        });
+    }
+}
+
+criterion_group!(benches, hash_chain_benchmark);
+criterion_main!(benches);

src/lib.rs

@@ -476,6 +476,7 @@ mod tests {
         >>::build_hash_chain_circuit(&mut circuit, 2)
         .unwrap();
 
+        let num_bytes = proof.to_bytes().len();
         let result =
             <CircuitBuilder<GoldilocksField, D> as HashChain<GoldilocksField, D, C>>::verify(
                 proof,