diff --git a/12-optimizations/91-cpu-caches/predictability/main_test.go b/12-optimizations/91-cpu-caches/predictability/main_test.go
new file mode 100644
index 0000000..9ecab05
--- /dev/null
+++ b/12-optimizations/91-cpu-caches/predictability/main_test.go
@@ -0,0 +1,32 @@
+package main
+
+import "testing"
+
+var global int64
+
+const n = 1_000_000
+
+func BenchmarkLinkedList(b *testing.B) {
+	var local int64
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		nodes := make([]node, n)
+		for i := 0; i < n-1; i++ {
+			nodes[i].next = &nodes[i+1]
+		}
+		b.StartTimer()
+		local = linkedList(&nodes[0])
+	}
+	global = local
+}
+
+func BenchmarkSum2(b *testing.B) {
+	var local int64
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		s := make([]int64, n)
+		b.StartTimer()
+		local = sum2(s)
+	}
+	global = local
+}