+
/* The file contais the clock task, which handles all time related functions.
* Important events that are handled by the CLOCK include alarm timers and
* (re)scheduling user processes.
* Sep 30, 2004 source code documentation updated (Jorrit N. Herder)
* Sep 24, 2004 redesigned alarm timers (Jorrit N. Herder)
*
- * The function do_clocktick() is not triggered by the clock's interrupt
+ * The function do_clocktick() is only triggered by the clocks interrupt
* handler when a watchdog timer has expired or a process must be scheduled.
*
* In addition to the main clock_task() entry point, which starts the main
* get_uptime: get realtime since boot in clock ticks
* set_timer: set a watchdog timer (+)
* reset_timer: reset a watchdog timer (+)
- * calc_elapsed: do timing measurements: get delta ticks and pulses
* read_clock: read the counter of channel 0 of the 8253A timer
*
* (+) The CLOCK task keeps tracks of watchdog timers for the entire kernel.
}
/* Check if do_clocktick() must be called. Done for alarms and scheduling.
- * Some processes, such as the kernel tasks, cannot be preempted.
+ * Even the clock and system tasks get finite, but large, quanta.
*/
if ((next_timeout <= realtime) || (proc_ptr->p_ticks_left <= 0)) {
prev_ptr = proc_ptr; /* store running process */