MirOS Manual: hardclock(9)

HARDCLOCK(9)                  BSD Kernel Manual                   HARDCLOCK(9)

NAME

     hardclock - real-time system clock

SYNOPSIS

     #include <sys/systm.h>

     void
     hardclock(struct clockframe *frame);

DESCRIPTION

     hardclock() implements the real-time system clock, interrupting hz(9)
     times a second. The argument frame is an opaque, machine dependent struc-
     ture that encapsulates the previous machine state.

     hardclock() performs a variety of time related housekeeping tasks, such
     as

           •   If the current process has virtual or profiling interval ti-
               mers, update the timers and deliver appropriate signals.

           •   If there is no separate statistics clock, execute statclock().

           •   Increment the time of day, implementing any adjustments re-
               quested by adjtime(2) or required as a result of running an NTP
               daemon or other configured external clock.

           •   Update the real-time timeout queue, calling softclock() direct-
               ly if the current interrupt priority is low enough.

SEE ALSO

     adjtime(2), hz(9), microtime(9), spl(9), time(9), timeout(9)

CODE REFERENCES

     hardclock() is implemented in the file sys/kern/kern_clock.c.

MirOS BSD #10-current           July 14, 2001                                1

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