Added benchmarks for polynomial multiplication and interpolation.

Cargo.toml

@@ -28,4 +28,10 @@ tiny-keccak = "1.4"
 
 [dev-dependencies]
 bincode = "1.0.0"
+criterion = "0.2"
+rand = "0.4.2"
 serde_derive = "1.0.55"
+
+[[bench]]
+name = "bench"
+harness = false

README.md

@@ -89,6 +89,17 @@ must tolerate up to `t` adversarial (malicious or faulty) nodes. Because `t +
 1` nodes are required to sign or reveal information, messages can be trusted
 by third-parties as representing the consensus of the network.
 
+## Performance
+
+Benchmarking functionality is kept in the [`benches` directory](benches). You
+can run the benchmarks with the following command:
+
+```
+$ RUSTFLAGS="-C target_cpu=native" cargo bench
+```
+
+We use the [`criterion`](https://crates.io/crates/criterion) benchmarking library.
+
 ## License
 
 Licensed under either of:

benches/bench.rs

@@ -0,0 +1,36 @@
+#[macro_use]
+extern crate criterion;
+extern crate rand;
+extern crate threshold_crypto;
+
+use criterion::Criterion;
+use threshold_crypto::poly::Poly;
+
+mod poly_benches {
+    use super::*;
+
+    // Benchmarks multiplication of two degree 3 polynomials.
+    fn multiplication(c: &mut Criterion) {
+        let mut rng = rand::thread_rng();
+        let lhs = Poly::random(3, &mut rng).unwrap();
+        let rhs = Poly::random(3, &mut rng).unwrap();
+        c.bench_function("Polynomial multiplication", move |b| b.iter(|| &lhs * &rhs));
+    }
+
+    // Benchmarks Lagrange interpolation for a degree 3 polynomial.
+    fn interpolate(c: &mut Criterion) {
+        // Points from the the polynomial: `y(x) = 5x^3 + 0x^2 + x - 2`.
+        let sample_points = vec![(-1, -8), (2, 40), (3, 136), (5, 628)];
+        c.bench_function("Polynomial interpolation", move |b| {
+            b.iter(|| Poly::interpolate(sample_points.clone()).unwrap())
+        });
+    }
+
+    criterion_group!{
+        name = poly_benches;
+        config = Criterion::default();
+        targets = multiplication, interpolate,
+    }
+}
+
+criterion_main!(poly_benches::poly_benches);