diff --git a/kern/libkern/util.h b/kern/libkern/util.h
new file mode 100644
index 0000000..ffb9cf2
--- /dev/null
+++ b/kern/libkern/util.h
@@ -0,0 +1,15 @@
+#ifndef UTIL_H
+#define UTIL_H
+
+/*
+ * Give hints to the compiler for branch prediction optimization.
+ */
+#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 2))
+#define likely(c)   (__builtin_expect(!!(c), 1))
+#define unlikely(c) (__builtin_expect(!!(c), 0))
+#else
+#define likely(c)   (c)
+#define unlikely(c) (c)
+#endif
+
+#endif // UTIL_H