+#if ENABLE_MONOTONIC_SYSCALL
+#include <sys/syscall.h>
+
+/* libc has incredibly messy way of doing this,
+ * typically requiring -lrt. We just skip all this mess */
+static void gettimeofday_ns(struct timespec *ts)
+{
+ syscall(__NR_clock_gettime, CLOCK_REALTIME, ts);
+}
+#else
+static void gettimeofday_ns(struct timespec *ts)
+{
+ if (sizeof(struct timeval) == sizeof(struct timespec)
+ && sizeof(((struct timeval*)ts)->tv_usec) == sizeof(ts->tv_nsec)
+ ) {
+ /* Cheat */
+ gettimeofday((void*)ts, NULL);
+ ts->tv_nsec *= 1000;
+ } else {
+ extern void BUG_need_to_implement_gettimeofday_ns(void);
+ BUG_need_to_implement_gettimeofday_ns();
+ }
+}
+#endif
+
+/* Compare possibly overflowing unsigned counters */
+#define LESS(a,b) ((int)((unsigned)(b) - (unsigned)(a)) > 0)