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minix/kernel/clock.h

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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));
Userspace scheduling - exporting stats - contributed by Bjorn Swift - adds process accounting, for example counting the number of messages sent, how often the process was preemted and how much time it spent in the run queue. These statistics, along with the current cpu load, are sent back to the user-space scheduler in the Out Of Quantum message. - the user-space scheduler may choose to make use of these statistics when making scheduling decisions. For isntance the cpu load becomes especially useful when scheduling on multiple cores.
2010-09-19 17:52:12 +02:00
_PROTOTYPE( unsigned cpu_time_2_ms, (u64_t cpu_time));
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
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__ */
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