chore: add benchmarks for erasure encoding and decoding

erasure_codes/Cargo.toml

@@ -11,3 +11,11 @@ repository = { workspace = true }
 [dependencies]
 bls12_381 = { workspace = true }
 polynomial = { workspace = true }
+
+[dev-dependencies]
+criterion = "0.5.1"
+rand = "0.8.4"
+
+[[bench]]
+name = "benchmark"
+harness = false

erasure_codes/benches/benchmark.rs

@@ -0,0 +1,58 @@
+use std::ops::Range;
+
+use bls12_381::Scalar;
+use crate_crypto_internal_peerdas_erasure_codes::{reed_solomon::Erasures, ReedSolomon};
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+
+pub fn bench_erasure_code_decoding_4096_8192(c: &mut Criterion) {
+    const POLYNOMIAL_LEN: usize = 4096;
+
+    let rs = ReedSolomon::new(POLYNOMIAL_LEN, 2);
+    let extended_poly_len = rs.extended_polynomial_length();
+
+    let mut encoded_polynomial = Vec::with_capacity(extended_poly_len);
+    for i in 0..extended_poly_len {
+        encoded_polynomial.push(black_box(-Scalar::from(i as u64 + 1)));
+    }
+
+    fn generate_unique_random_numbers(range: Range<usize>, n: usize) -> Vec<usize> {
+        use rand::prelude::SliceRandom;
+        let mut numbers: Vec<_> = range.into_iter().collect();
+        numbers.shuffle(&mut rand::thread_rng());
+        numbers.into_iter().take(n).collect()
+    }
+
+    let cell_size = 64;
+    let num_cells = extended_poly_len / cell_size;
+
+    let missing_cells = generate_unique_random_numbers(0..cell_size, num_cells / 2);
+
+    // Zero out the values in the polynomial that correspond to the cell_id
+    for cell in &missing_cells {
+        for i in 0..cell_size {
+            encoded_polynomial[*cell as usize * cell_size + i] = Scalar::from(0);
+        }
+    }
+
+    c.bench_function(
+        &format!(
+            "computing decoding: EXT_SIZE {}, MISSING_CELLS {}",
+            extended_poly_len,
+            num_cells / 2
+        ),
+        |b| {
+            b.iter(|| {
+                rs.recover_polynomial_codeword(
+                    encoded_polynomial.clone(),
+                    Erasures::Cells {
+                        cell_size,
+                        cells: missing_cells.clone(),
+                    },
+                )
+            })
+        },
+    );
+}
+
+criterion_group!(benches, bench_erasure_code_decoding_4096_8192);
+criterion_main!(benches);