Switch backup entropy generator to JitterRng

.travis.yml

@@ -12,6 +12,7 @@ matrix:
     - rust: beta
     - rust: nightly
       script:
+        - cargo bench
         - cargo test
         - cargo test --features nightly
         - cargo test --manifest-path rand-derive/Cargo.toml

appveyor.yml

@@ -32,6 +32,7 @@ install:
 build: false
 
 test_script:
+  - cargo bench
   - cargo test
   - cargo test --features nightly
   - cargo test --manifest-path rand-derive/Cargo.toml

benches/bench.rs

@@ -9,9 +9,18 @@ mod distributions;
 
 use std::mem::size_of;
 use test::{black_box, Bencher};
-use rand::{XorShiftRng, StdRng, IsaacRng, Isaac64Rng, Rng};
+use rand::{XorShiftRng, StdRng, IsaacRng, Isaac64Rng, JitterRng, Rng};
 use rand::{OsRng, sample, weak_rng};
 
+#[bench]
+fn rand_jitter(b: &mut Bencher) {
+    let mut rng = JitterRng::new().unwrap();
+    b.iter(|| {
+        black_box(rng.next_u64());
+    });
+    b.bytes = size_of::<u64>() as u64;
+}
+
 #[bench]
 fn rand_xorshift(b: &mut Bencher) {
     let mut rng: XorShiftRng = OsRng::new().unwrap().gen();