Index: libcfa/src/bits/defs.hfa
===================================================================
--- libcfa/src/bits/defs.hfa	(revision 2026bb680ed5d5d8295cce3291a89b31b8ec7de2)
+++ libcfa/src/bits/defs.hfa	(revision 1a69a908039a3c69a0d43b7089553d900c60df5b)
@@ -47,2 +47,8 @@
 #define OPTIONAL_THREAD __attribute__((weak))
 #endif
+
+static inline long long rdtscl(void) {
+    unsigned int lo, hi;
+    __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
+    return ( (unsigned long long)lo)|( ((unsigned long long)hi)<<32 );
+}