bitv: make sure benchmarks run long enough

Previously they were too short (less than 10 ns), so the benchmarker
could not resolve them meaningfully. Now they should run in the order of
100 ns.

Author: vks

src/libcollections/bitv.rs

@@ -2566,7 +2566,9 @@ mod tests {
         let mut r = rng();
         let mut bitv = 0 as uint;
         b.iter(|| {
-            bitv |= 1 << ((r.next_u32() as uint) % uint::BITS);
+            for _ in range(0u, 100) {
+                bitv |= 1 << ((r.next_u32() as uint) % uint::BITS);
+            }
             &bitv
         })
     }
@@ -2576,7 +2578,9 @@ mod tests {
         let mut r = rng();
         let mut bitv = Bitv::with_capacity(BENCH_BITS, false);
         b.iter(|| {
-            bitv.set((r.next_u32() as uint) % BENCH_BITS, true);
+            for _ in range(0u, 100) {
+                bitv.set((r.next_u32() as uint) % BENCH_BITS, true);
+            }
             &bitv
         })
     }
@@ -2586,7 +2590,9 @@ mod tests {
         let mut r = rng();
         let mut bitv = Bitv::with_capacity(uint::BITS, false);
         b.iter(|| {
-            bitv.set((r.next_u32() as uint) % uint::BITS, true);
+            for _ in range(0u, 100) {
+                bitv.set((r.next_u32() as uint) % uint::BITS, true);
+            }
             &bitv
         })
     }
@@ -2596,7 +2602,9 @@ mod tests {
         let mut r = rng();
         let mut bitv = BitvSet::new();
         b.iter(|| {
-            bitv.insert((r.next_u32() as uint) % uint::BITS);
+            for _ in range(0u, 100) {
+                bitv.insert((r.next_u32() as uint) % uint::BITS);
+            }
             &bitv
         })
     }
@@ -2606,7 +2614,9 @@ mod tests {
         let mut r = rng();
         let mut bitv = BitvSet::new();
         b.iter(|| {
-            bitv.insert((r.next_u32() as uint) % BENCH_BITS);
+            for _ in range(0u, 100) {
+                bitv.insert((r.next_u32() as uint) % BENCH_BITS);
+            }
             &bitv
         })
     }
@@ -2625,8 +2635,10 @@ mod tests {
         let bitv = Bitv::with_capacity(uint::BITS, false);
         b.iter(|| {
             let mut sum = 0;
-            for pres in bitv.iter() {
-                sum += pres as uint;
+            for _ in range(0u, 10) {
+                for pres in bitv.iter() {
+                    sum += pres as uint;
+                }
             }
             sum
         })