Add benchmarking.

README.md

@@ -8,3 +8,42 @@ $ ./target/fibs
 $ ./target/fibs2
 $ ./target/fibs3
 ```
+
+To benchmark:
+
+Cargo doesn't have a bench command yet, so you have to fudge it:
+
+```bash
+$ cargo test
+$ target/tests/fibs1 --bench
+$ target/tests/fibs2 --bench
+$ target/tests/fibs3 --bench
+```
+
+On my system:
+
+```
+steve@computer:~/tmp/fibs$ target/tests/fibs1 --bench
+
+running 1 test
+test bench_fib_of_40000000 ... bench:       624 ns/iter (+/- 10)
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 1 measured
+
+steve@computer:~/tmp/fibs$ target/tests/fibs2 --bench
+
+running 1 test
+test bench_fib_of_40000000 ... bench:       705 ns/iter (+/- 10)
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 1 measured
+
+steve@computer:~/tmp/fibs$ target/tests/fibs3 --bench
+
+running 1 test
+test bench_fib_of_40000000 ... bench:      1194 ns/iter (+/- 31)
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 1 measured
+
+```
+
+I am not sure why the last version is slower...

src/fibs1.rs

@@ -1,3 +1,6 @@
+extern crate test;
+use self::test::Bencher;
+
 fn fib(pred: |x: int| -> bool) {
     let mut previous = 1;
     let mut current = 1;
@@ -28,3 +31,25 @@ fn main() {
             });
     println!("sum = {}", sum)
 }
+
+#[bench]
+fn bench_fib_of_40000000(b: &mut Bencher) {
+    b.iter(|| {
+      let mut sum = 0;
+      fib(|i| -> bool {
+        if i > 4000000 {
+          // more or less a `break`
+          return false
+        }
+
+        if i % 2 != 0 {
+          // more or less `next`
+          return true
+        }
+
+        sum += i;
+
+        true
+      });
+    });
+}

src/fibs2.rs

@@ -1,3 +1,6 @@
+extern crate test;
+use self::test::Bencher;
+
 struct FibIter {
     previous: int,
     current: int
@@ -28,3 +31,18 @@ fn main() {
     }
     println!("sum = {}", sum);
 }
+
+#[bench]
+fn bench_fib_of_40000000(b: &mut Bencher) {
+    b.iter(|| {
+        let mut sum = 0;
+        for i in fib_iter() {
+            if i > 4000000 {
+                break;
+            }
+            if i % 2 == 0 {
+                sum += i;
+            }
+        }
+    });
+}

src/fibs3.rs

@@ -1,3 +1,6 @@
+extern crate test;
+use self::test::Bencher;
+
 struct FibIter {
 previous: int,
               current: int
@@ -23,3 +26,13 @@ fn main() {
         .fold(0, |acc, i| acc + i);
     println!("sum = {}", sum);
 }
+
+#[bench]
+fn bench_fib_of_40000000(b: &mut Bencher) {
+    b.iter(|| {
+      let sum = fib_iter()
+          .take_while(|&i| i < 4000000)
+          .filter(|&i| i % 2 == 0)
+          .fold(0, |acc, i| acc + i);
+    });
+}