static unsigned volatile last_jiffy_time;
-#define CLOCK_TICKS_PER_USEC (CLOCK_TICK_RATE / USEC_PER_SEC)
+#define CLOCK_TICKS_PER_USEC ((CLOCK_TICK_RATE + USEC_PER_SEC/2) / USEC_PER_SEC)
/* IRQs are disabled before entering here from do_gettimeofday() */
static unsigned long ixp4xx_gettimeoffset(void)