Index: sys/sys/time.h
===================================================================
--- sys/sys/time.h	(revision 242924)
+++ sys/sys/time.h	(working copy)
@@ -55,6 +55,21 @@ struct bintime {
 	uint64_t frac;
 };
 
+extern int tc_timethreshold;
+extern struct bintime tick_bt;
+
+#define FREQ2BT(freq, bt)                                               \
+{                                                                       \
+        (bt)->sec = 0;                                                  \
+        (bt)->frac = ((uint64_t)0x8000000000000000  / (freq)) << 1;     \
+}
+#define BT2FREQ(bt)                                                     \
+        (((uint64_t)0x8000000000000000 + ((bt)->frac >> 2)) /           \
+            ((bt)->frac >> 1))
+
+#define TIMESEL(x, bt)          					\
+	(((x) < (c_timethreshold)) ? binuptime(&bt) : getbinuptime(&bt))
+
 static __inline void
 bintime_addx(struct bintime *bt, uint64_t x)
 {
Index: sys/kern/kern_tc.c
===================================================================
--- sys/kern/kern_tc.c	(revision 242924)
+++ sys/kern/kern_tc.c	(working copy)
@@ -119,6 +119,11 @@ static int timestepwarnings;
 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
     &timestepwarnings, 0, "Log time steps");
 
+int tc_timethreshold;
+struct bintime tick_bt;
+SYSCTL_INT(_kern, OID_AUTO, tc_timethreshold, CTLFLAG_RW, 
+    &tc_timethreshold, 0, "Precision threshold for timing measurements"); 
+
 static void tc_windup(void);
 static void cpu_tick_calibrate(int);
 
@@ -1708,6 +1713,7 @@ tc_ticktock(int cnt)
 static void
 inittimecounter(void *dummy)
 {
+	int tick_rate;
 	u_int p;
 
 	/*
@@ -1723,6 +1729,9 @@ inittimecounter(void *dummy)
 	else
 		tc_tick = 1;
 	p = (tc_tick * 1000000) / hz;
+	tc_timethreshold = 20 * imin(1000000000 / hz, 1000000);
+        tick_rate = imax(hz, tc_tick);
+	FREQ2BT(tick_rate, &tick_bt);
 	printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
 
 #ifdef FFCLOCK
@@ -1928,3 +1937,4 @@ tc_fill_vdso_timehands32(struct vdso_timehands32 *
 	return (enabled);
 }
 #endif
+
Index: sys/kern/kern_timeout.c
===================================================================
--- sys/kern/kern_timeout.c	(revision 242924)
+++ sys/kern/kern_timeout.c	(working copy)
@@ -55,6 +55,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/sleepqueue.h>
 #include <sys/sysctl.h>
 #include <sys/smp.h>
+#include <sys/time.h>
 
 #ifdef SMP
 #include <machine/cpu.h>
@@ -171,12 +172,6 @@ struct callout_cpu cc_cpu;
 #define	CC_UNLOCK(cc)	mtx_unlock_spin(&(cc)->cc_lock)
 #define	CC_LOCK_ASSERT(cc)	mtx_assert(&(cc)->cc_lock, MA_OWNED)
 
-#define FREQ2BT(freq, bt)                                               \
-{                                                                       \
-        (bt)->sec = 0;                                                  \
-        (bt)->frac = ((uint64_t)0x8000000000000000  / (freq)) << 1;     \
-}
-
 #define	TIME_T_MAX							\
 	(sizeof(time_t) == (sizeof(int64_t)) ? INT64_MAX : INT32_MAX)
 
Index: sys/kern/kern_clocksource.c
===================================================================
--- sys/kern/kern_clocksource.c	(revision 242924)
+++ sys/kern/kern_clocksource.c	(working copy)
@@ -147,15 +147,6 @@ struct pcpu_state {
 
 static DPCPU_DEFINE(struct pcpu_state, timerstate);
 
-#define FREQ2BT(freq, bt)						\
-{									\
-	(bt)->sec = 0;							\
-	(bt)->frac = ((uint64_t)0x8000000000000000  / (freq)) << 1;	\
-}
-#define BT2FREQ(bt)							\
-	(((uint64_t)0x8000000000000000 + ((bt)->frac >> 2)) /		\
-	    ((bt)->frac >> 1))
-
 /*
  * Timer broadcast IPI handler.
  */