minix/kernel/clock.h

#ifndef __CLOCK_H__
#define __CLOCK_H__

#include "kernel.h"
#include "arch_clock.h"

_PROTOTYPE(int boot_cpu_init_timer, (unsigned freq));
_PROTOTYPE(int app_cpu_init_timer, (unsigned freq));

_PROTOTYPE(int timer_int_handler, (void));

_PROTOTYPE(int init_local_timer, (unsigned freq));
/* sto p the local timer ticking */
_PROTOTYPE(void stop_local_timer, (void));
/* let the time tick again with the original settings after it was stopped */
_PROTOTYPE(void restart_local_timer, (void));
_PROTOTYPE(int register_local_timer_handler, (irq_handler_t handler));

_PROTOTYPE( u64_t ms_2_cpu_time, (unsigned ms));

#endif /* __CLOCK_H__ */
Clock task split - preemption handled in the clock timer interrupt handler, not in the clock task - more achitecture independent clock timer handling code - smp ready as each CPU can have its own timer 2009-11-06 10:04:15 +01:00			`#ifndef __CLOCK_H__`
			`#define __CLOCK_H__`

			`#include "kernel.h"`
Convert kernel over to bsdmake 2010-04-02 00:22:33 +02:00			`#include "arch_clock.h"`
Clock task split - preemption handled in the clock timer interrupt handler, not in the clock task - more achitecture independent clock timer handling code - smp ready as each CPU can have its own timer 2009-11-06 10:04:15 +01:00
			`_PROTOTYPE(int boot_cpu_init_timer, (unsigned freq));`
SMP - Only a single APIC timer handler - bsp_timer_int_handler() and ap_timer_int_handler() unified into timer_int_handler() - global realtime updated only on BSP 2010-09-15 16:10:09 +02:00			`_PROTOTYPE(int app_cpu_init_timer, (unsigned freq));`
Clock task split - preemption handled in the clock timer interrupt handler, not in the clock task - more achitecture independent clock timer handling code - smp ready as each CPU can have its own timer 2009-11-06 10:04:15 +01:00
SMP - Only a single APIC timer handler - bsp_timer_int_handler() and ap_timer_int_handler() unified into timer_int_handler() - global realtime updated only on BSP 2010-09-15 16:10:09 +02:00			`_PROTOTYPE(int timer_int_handler, (void));`
Clock task split - preemption handled in the clock timer interrupt handler, not in the clock task - more achitecture independent clock timer handling code - smp ready as each CPU can have its own timer 2009-11-06 10:04:15 +01:00
SMP - Single shot local timer - APIC timer always reprogrammed if expired - timer tick never happens when in kernel => never immediate return from userspace to kernel because of a buffered interrupt - renamed argument to lapic_set_timer_one_shot() - removed arch_ prefix from timer functions 2010-09-15 16:11:06 +02:00			`_PROTOTYPE(int init_local_timer, (unsigned freq));`
SMP - trully idle APs - any cpu can use smp_schedule() to tell another cpu to reschedule - if an AP is idle, it turns off timer as there is nothing to preempt, no need to wakeup just to go back to sleep again - if a cpu makes a process runnable on an idle cpu, it must wake it up to reschedule 2010-09-15 16:10:57 +02:00			`/* sto p the local timer ticking */`
SMP - Single shot local timer - APIC timer always reprogrammed if expired - timer tick never happens when in kernel => never immediate return from userspace to kernel because of a buffered interrupt - renamed argument to lapic_set_timer_one_shot() - removed arch_ prefix from timer functions 2010-09-15 16:11:06 +02:00			`_PROTOTYPE(void stop_local_timer, (void));`
SMP - trully idle APs - any cpu can use smp_schedule() to tell another cpu to reschedule - if an AP is idle, it turns off timer as there is nothing to preempt, no need to wakeup just to go back to sleep again - if a cpu makes a process runnable on an idle cpu, it must wake it up to reschedule 2010-09-15 16:10:57 +02:00			`/* let the time tick again with the original settings after it was stopped */`
SMP - Single shot local timer - APIC timer always reprogrammed if expired - timer tick never happens when in kernel => never immediate return from userspace to kernel because of a buffered interrupt - renamed argument to lapic_set_timer_one_shot() - removed arch_ prefix from timer functions 2010-09-15 16:11:06 +02:00			`_PROTOTYPE(void restart_local_timer, (void));`
			`_PROTOTYPE(int register_local_timer_handler, (irq_handler_t handler));`
Clock task split - preemption handled in the clock timer interrupt handler, not in the clock task - more achitecture independent clock timer handling code - smp ready as each CPU can have its own timer 2009-11-06 10:04:15 +01:00
scheduling - time quantum in miliseconds - Currently the cpu time quantum is timer-ticks based. Thus the remaining quantum is decreased only if the processes is interrupted by a timer tick. As processes block a lot this typically does not happen for normal user processes. Also the quantum depends on the frequency of the timer. - This change makes the quantum miliseconds based. Internally the miliseconds are translated into cpu cycles. Everytime userspace execution is interrupted by kernel the cycles just consumed by the current process are deducted from the remaining quantum. - It makes the quantum system timer frequency independent. - The boot processes quantum is loosely derived from the tick-based quantas and 60Hz timer and subject to future change - the 64bit arithmetics is a little ugly, will be changes once we have compiler support for 64bit integers (soon) 2010-05-25 10:06:14 +02:00			`_PROTOTYPE( u64_t ms_2_cpu_time, (unsigned ms));`

Clock task split - preemption handled in the clock timer interrupt handler, not in the clock task - more achitecture independent clock timer handling code - smp ready as each CPU can have its own timer 2009-11-06 10:04:15 +01:00			`#endif /* __CLOCK_H__ */`