Added black_box, currently unused; changed computation.

benchmarks/toy-rs/src/main.rs

@@ -1,18 +1,39 @@
 #[allow(unused)]
 use coz;
 use std::thread;
-#[no_mangle]
+
-pub fn a_first_fn() {
+fn black_box<T>(dummy: T) -> T {
-    for _x in 0..2000000 {}
+    unsafe {
+        std::ptr::read_volatile(&dummy)
+    }
 }
 
 #[no_mangle]
-pub fn b_second_fn() {
+pub fn a_first_fn() -> i64 {
-    for _y in 0..1900000 {}
+    let mut v: i64 = 0;
+    for x in 0..200000000 {
+	v += x * x;
+	v -= x * x;
+	v += x * x;
+	v -= x * x;
+    }
+    return v;
+}
+
+#[no_mangle]
+pub fn b_second_fn() -> i64 {
+    let mut v: i64 = 0;
+    for x in 0..100000000 {
+	v += x * x;
+	v -= x * x;
+	v += x * x;
+	v -= x * x;
+    }
+    return v;
 }
 
 fn main() {
-    for _n in 1..1000 {
+    for _n in 1..100 {
       let handle1 = thread::spawn(|| a_first_fn());
       let handle2 = thread::spawn(|| b_second_fn());
       handle1.join().unwrap();