Index: share/man/man9/hardclock.9
===================================================================
--- share/man/man9/hardclock.9
+++ share/man/man9/hardclock.9
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd March 25, 2010
+.Dd July 1, 2021
 .Dt HARDCLOCK 9
 .Os
 .Sh NAME
@@ -39,19 +39,24 @@
 .Sh DESCRIPTION
 The
 .Fn hardclock
-function is called
-.Xr hz 9
-times per second.
+function is called twice or more times per second.
 It implements the real-time system clock.
 The argument
 .Va cnt
 is the estimated number of ticks since the last call to
 .Fn hardclock .
+At a high level, the sum of the
+.Va cnt
+argument to successive calls averages to about
+.Va hz
+per second over the long haul, however
+.Xr hz 9
+has important details relevant on shorter time scales.
 The argument
 .Va usermode
 is none-zero when
 .Fn hardclock
-is called from a user-mode context.
+is called from an context that interrupted usermode execution.
 .Pp
 .Fn hardclock
 may perform different tasks such as:
@@ -96,5 +101,4 @@
 .Xr ntp_adjtime 2 ,
 .Xr signal 3 ,
 .Xr ntpd 8 ,
-.Xr callout 9 ,
 .Xr hz 9