+//ust// static inline u64 trace_clock_read64(void)
+//ust// {
+//ust// uint32_t low;
+//ust// uint32_t high;
+//ust// uint64_t retval;
+//ust// __asm__ volatile ("rdtsc\n" : "=a" (low), "=d" (high));
+//ust//
+//ust// retval = high;
+//ust// retval <<= 32;
+//ust// return retval | low;
+//ust// }
+