feat: benchmark RPO

Cargo.toml

@@ -10,6 +10,10 @@ categories = ["cryptography", "no-std"]
 keywords = ["miden", "crypto", "hash", "merkle"]
 edition = "2021"
 
+[[bench]]
+name = "hash"
+harness = false
+
 [features]
 default = ["std", "winter_crypto/default", "winter_math/default", "winter_utils/default"]
 std = ["winter_crypto/std", "winter_math/std", "winter_utils/std"]
@@ -22,3 +26,4 @@ winter_utils = { version = "0.4.1", package = "winter-utils", default-features =
 [dev-dependencies]
 proptest = "1.0.0"
 rand_utils = { version = "0.4", package = "winter-rand-utils" }
+criterion = "0.3"

benches/hash.rs

@@ -0,0 +1,56 @@
+
+
+use criterion::{black_box, criterion_group, criterion_main, BatchSize, Criterion};
+use miden_crypto::{hash::{Hasher, Digest}, HashFn, Felt, ElementHasher};
+use rand_utils::rand_value;
+
+fn rpo256_2to1(c: &mut Criterion) {
+    let v: [Digest; 2] = [Hasher::hash(&[1u8]), Hasher::hash(&[2u8])];
+    c.bench_function("RPO256 2-to-1 hashing (cached)", |bench| {
+        bench.iter(|| Hasher::merge(black_box(&v)))
+    });
+
+    c.bench_function("RPO256 2-to-1 hashing (random)", |bench| {
+        bench.iter_batched(
+            || {
+                [
+                    Hasher::hash(&rand_value::<u64>().to_le_bytes()),
+                    Hasher::hash(&rand_value::<u64>().to_le_bytes()),
+                ]
+            },
+            |state| Hasher::merge(&state),
+            BatchSize::SmallInput,
+        )
+    });
+}
+
+fn rpo256_sequential(c: &mut Criterion) {
+    let v: [Felt; 100] = (0..100)
+        .into_iter()
+        .map(Felt::new)
+        .collect::<Vec<Felt>>()
+        .try_into()
+        .expect("should not fail");
+    c.bench_function("RPO256 sequential hashing (cached)", |bench| {
+        bench.iter(|| Hasher::hash_elements(black_box(&v)))
+    });
+
+    c.bench_function("RPO256 sequential hashing (random)", |bench| {
+        bench.iter_batched(
+            || {
+                let v: [Felt; 100] = (0..100)
+                    .into_iter()
+                    .map(|_| Felt::new(rand_value()))
+                    .collect::<Vec<Felt>>()
+                    .try_into()
+                    .expect("should not fail");
+                v
+            },
+            |state| Hasher::hash_elements(&state),
+            BatchSize::SmallInput,
+        )
+    });
+}
+
+criterion_group!(hash_group, rpo256_sequential, rpo256_2to1);
+criterion_main!(hash_group);