diff --git a/src/libcollections/bitv.rs b/src/libcollections/bitv.rs
index cb4e3c82be5c..10ebcbcab36b 100644
--- a/src/libcollections/bitv.rs
+++ b/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
         })