DragonFly On-Line Manual Pages

TVTOHZ(9)             DragonFly Kernel Developer's Manual            TVTOHZ(9)

NAME
     tvtohz_high, tvtohz_low -- convert time interval to tick count

SYNOPSIS
     #include <sys/time.h>

     int
     tvtohz_high(struct timeval *tv);

     int
     tvtohz_low(struct timeval *tv);

DESCRIPTION
     The tvtohz_high() and tvtohz_low() functions accept a single argument tv
     which specifies the time interval over which to calculate the number of
     system ticks that would elapse.

RETURN VALUES
     The tvtohz_high() function returns the integral number of system ticks
     expected to elapse in the given interval.  The return value is intended
     to be used in a clock interrupt timed operation and guaranteed to meet or
     exceed the requested time.  The minimum return value is 1 tick and the
     function will average the calculation up.  If any value greater than 0
     microseconds is supplied, a value of at least 2 will be returned to
     ensure that a near-term clock interrupt does not cause the timeout to
     occur (degenerately) early.

     The tvtohz_low() function returns the uncompensated number of system
     ticks for the specified amount of time.  A return value of 0 is possible
     if tv converts to less than 1 tick.

     If the reprensentation overflows, both functions return INT_MAX.

FILES
     sys/kern/kern_clock.c

SEE ALSO
     callout(9), microtime(9), microuptime(9)

HISTORY
     The tvtohz function first appeared in FreeBSD 3.0.  It was split into
     tvtohz_high and tvtohz_low by Matt Dillon in DragonFly 1.0.

AUTHORS
     This manual page was originally written by Kelly Yancey <kbyanc@posi.net>
     and later updated by Sascha Wildner.

DragonFly 3.5                    June 30, 2007                   DragonFly 3.5