-
-/*
- * Define shifts for simulating (5/8)**n
- */
-
-shift_data_t wait_shift[32] = {
- {1,1},{1,3},{1,-3},{2,-7},{3,5},{3,-5},{4,-8},{5,7},
- {5,-7},{6,-10},{7,10},{7,-9},{8,-11},{9,12},{9,-11},{10,-13},
- {11,14},{11,-13},{12,-15},{13,17},{13,-15},{14,-17},{15,19},{16,18},
- {16,-19},{17,22},{18,20},{18,-20},{19,26},{20,22},{20,-22},{21,-27}};
-
-/*
- * do_priority_computation:
- *
- * Calculate new priority for thread based on its base priority plus
- * accumulated usage. PRI_SHIFT and PRI_SHIFT_2 convert from
- * usage to priorities. SCHED_SHIFT converts for the scaling
- * of the sched_usage field by SCHED_SCALE. This scaling comes
- * from the multiplication by sched_load (thread_timer_delta)
- * in sched.h. sched_load is calculated as a scaled overload
- * factor in compute_mach_factor (mach_factor.c).
- */
-#ifdef PRI_SHIFT_2
-#if PRI_SHIFT_2 > 0
-#define do_priority_computation(thread, pri) \
- MACRO_BEGIN \
- (pri) = (thread)->priority /* start with base priority */ \
- - ((thread)->sched_usage >> (PRI_SHIFT + SCHED_SHIFT)) \
- - ((thread)->sched_usage >> (PRI_SHIFT_2 + SCHED_SHIFT)); \
- if ((pri) < MINPRI_STANDARD) \
- (pri) = MINPRI_STANDARD; \
- else \
- if ((pri) > MAXPRI_STANDARD) \
- (pri) = MAXPRI_STANDARD; \
- MACRO_END
-#else /* PRI_SHIFT_2 */
-#define do_priority_computation(thread, pri) \
- MACRO_BEGIN \
- (pri) = (thread)->priority /* start with base priority */ \
- - ((thread)->sched_usage >> (PRI_SHIFT + SCHED_SHIFT)) \
- + ((thread)->sched_usage >> (SCHED_SHIFT - PRI_SHIFT_2)); \
- if ((pri) < MINPRI_STANDARD) \
- (pri) = MINPRI_STANDARD; \
- else \
- if ((pri) > MAXPRI_STANDARD) \
- (pri) = MAXPRI_STANDARD; \
- MACRO_END
-#endif /* PRI_SHIFT_2 */
-#else /* defined(PRI_SHIFT_2) */
-#define do_priority_computation(thread, pri) \
- MACRO_BEGIN \
- (pri) = (thread)->priority /* start with base priority */ \
- - ((thread)->sched_usage >> (PRI_SHIFT + SCHED_SHIFT)); \
- if ((pri) < MINPRI_STANDARD) \
- (pri) = MINPRI_STANDARD; \
- else \
- if ((pri) > MAXPRI_STANDARD) \
- (pri) = MAXPRI_STANDARD; \
- MACRO_END
-#endif /* defined(PRI_SHIFT_2) */
-
-void
-set_priority(
- register thread_t thread,
- register int priority)
-{
- thread->priority = priority;
- compute_priority(thread, FALSE);
-}
-
-/*
- * compute_priority:
- *
- * Reset the current scheduled priority of the
- * thread according to its base priority if the
- * thread has not been promoted or depressed.
- *
- * If the thread is timesharing, adjust according
- * to recent cpu usage.
- *
- * The thread *must* be locked by the caller.
- */
-void
-compute_priority(
- register thread_t thread,
- boolean_t override_depress)
-{
- register int priority;
-
- if ( !(thread->sched_mode & TH_MODE_PROMOTED) &&
- (!(thread->sched_mode & TH_MODE_ISDEPRESSED) ||
- override_depress ) ) {
- if (thread->sched_mode & TH_MODE_TIMESHARE)
- do_priority_computation(thread, priority);
- else
- priority = thread->priority;
-
- set_sched_pri(thread, priority);
- }
-}
-
-/*
- * compute_my_priority:
- *
- * Version of compute priority for current thread.
- * Caller must have thread locked and thread must
- * be timesharing and not depressed.
- *
- * Only used for priority updates.
- */
-void
-compute_my_priority(
- register thread_t thread)
-{
- register int priority;
-
- do_priority_computation(thread, priority);
- assert(thread->runq == RUN_QUEUE_NULL);
- thread->sched_pri = priority;
-}
-
-/*
- * update_priority
- *
- * Cause the priority computation of a thread that has been
- * sleeping or suspended to "catch up" with the system. Thread
- * *MUST* be locked by caller. If thread is running, then this
- * can only be called by the thread on itself.
- */
-void
-update_priority(
- register thread_t thread)
-{
- register unsigned int ticks;
- register shift_t shiftp;
-
- ticks = sched_tick - thread->sched_stamp;
- assert(ticks != 0);
-
- /*
- * If asleep for more than 30 seconds forget all
- * cpu_usage, else catch up on missed aging.
- * 5/8 ** n is approximated by the two shifts
- * in the wait_shift array.
- */
- thread->sched_stamp += ticks;
- thread_timer_delta(thread);
- if (ticks > 30) {
- thread->cpu_usage = 0;
- thread->sched_usage = 0;
- }
- else {
- thread->cpu_usage += thread->cpu_delta;
- thread->sched_usage += thread->sched_delta;
-
- shiftp = &wait_shift[ticks];
- if (shiftp->shift2 > 0) {
- thread->cpu_usage =
- (thread->cpu_usage >> shiftp->shift1) +
- (thread->cpu_usage >> shiftp->shift2);
- thread->sched_usage =
- (thread->sched_usage >> shiftp->shift1) +
- (thread->sched_usage >> shiftp->shift2);
- }
- else {
- thread->cpu_usage =
- (thread->cpu_usage >> shiftp->shift1) -
- (thread->cpu_usage >> -(shiftp->shift2));
- thread->sched_usage =
- (thread->sched_usage >> shiftp->shift1) -
- (thread->sched_usage >> -(shiftp->shift2));
- }
- }
-
- thread->cpu_delta = 0;
- thread->sched_delta = 0;
-
- /*
- * Check for fail-safe release.
- */
- if ( (thread->sched_mode & TH_MODE_FAILSAFE) &&
- thread->sched_stamp >= thread->safe_release ) {
- if (!(thread->safe_mode & TH_MODE_TIMESHARE)) {
- if (thread->safe_mode & TH_MODE_REALTIME) {
- thread->priority = BASEPRI_REALTIME;
-
- thread->sched_mode |= TH_MODE_REALTIME;
- }
-
- thread->sched_mode &= ~TH_MODE_TIMESHARE;
-
- if (!(thread->sched_mode & TH_MODE_ISDEPRESSED))
- set_sched_pri(thread, thread->priority);
- }
-
- thread->safe_mode = 0;
- thread->sched_mode &= ~TH_MODE_FAILSAFE;
- }
-
- /*
- * Recompute scheduled priority if appropriate.
- */
- if ( (thread->sched_mode & TH_MODE_TIMESHARE) &&
- !(thread->sched_mode & TH_MODE_PROMOTED) &&
- !(thread->sched_mode & TH_MODE_ISDEPRESSED) ) {
- register int new_pri;
-
- do_priority_computation(thread, new_pri);
- if (new_pri != thread->sched_pri) {
- run_queue_t runq;
-
- runq = rem_runq(thread);
- thread->sched_pri = new_pri;
- if (runq != RUN_QUEUE_NULL)
- thread_setrun(thread, TAIL_Q);
- }
- }
-}
-
-/*
- * thread_switch_continue:
- *
- * Continuation routine for a thread switch.
- *
- * Just need to arrange the return value gets sent out correctly and that
- * we cancel the timer or the depression called for by the options to the
- * thread_switch call.
- */
-void
-_mk_sp_thread_switch_continue(void)
-{
- register thread_t self = current_thread();
- int wait_result = self->wait_result;
- int option = self->saved.swtch.option;
-
- if (option == SWITCH_OPTION_WAIT && wait_result != THREAD_TIMED_OUT)
- thread_cancel_timer();
- else
- if (option == SWITCH_OPTION_DEPRESS)
- _mk_sp_thread_depress_abort(self, FALSE);
-
- thread_syscall_return(KERN_SUCCESS);
- /*NOTREACHED*/
-}
-
-/*
- * thread_switch:
- *
- * Context switch. User may supply thread hint.
- *
- * Fixed priority threads that call this get what they asked for
- * even if that violates priority order.
- */
-kern_return_t
-_mk_sp_thread_switch(
- thread_act_t hint_act,
- int option,
- mach_msg_timeout_t option_time)
-{
- register thread_t self = current_thread();
- register processor_t myprocessor;
- int s;
-
- /*
- * Check and use thr_act hint if appropriate. It is not
- * appropriate to give a hint that shares the current shuttle.
- */
- if (hint_act != THR_ACT_NULL) {
- register thread_t thread = act_lock_thread(hint_act);
-
- if ( thread != THREAD_NULL &&
- thread != self &&
- thread->top_act == hint_act ) {
- s = splsched();
- thread_lock(thread);
-
- /*
- * Check if the thread is in the right pset. Then
- * pull it off its run queue. If it
- * doesn't come, then it's not eligible.
- */
- if ( thread->processor_set == self->processor_set &&
- rem_runq(thread) != RUN_QUEUE_NULL ) {
- /*
- * Hah, got it!!
- */
- thread_unlock(thread);
-
- act_unlock_thread(hint_act);
- act_deallocate(hint_act);
-
- if (option == SWITCH_OPTION_WAIT)
- assert_wait_timeout(option_time, THREAD_ABORTSAFE);
- else
- if (option == SWITCH_OPTION_DEPRESS)
- _mk_sp_thread_depress_ms(option_time);
-
- self->saved.swtch.option = option;
-
- thread_run(self, _mk_sp_thread_switch_continue, thread);
- /* NOTREACHED */
- }
-
- thread_unlock(thread);
- splx(s);
- }
-
- act_unlock_thread(hint_act);
- act_deallocate(hint_act);
- }
-
- /*
- * No handoff hint supplied, or hint was wrong. Call thread_block() in
- * hopes of running something else. If nothing else is runnable,
- * thread_block will detect this. WARNING: thread_switch with no
- * option will not do anything useful if the thread calling it is the
- * highest priority thread (can easily happen with a collection
- * of timesharing threads).
- */
- mp_disable_preemption();
- myprocessor = current_processor();
- if ( option != SWITCH_OPTION_NONE ||
- myprocessor->processor_set->runq.count > 0 ||
- myprocessor->runq.count > 0 ) {
- mp_enable_preemption();
-
- if (option == SWITCH_OPTION_WAIT)
- assert_wait_timeout(option_time, THREAD_ABORTSAFE);
- else
- if (option == SWITCH_OPTION_DEPRESS)
- _mk_sp_thread_depress_ms(option_time);
-
- self->saved.swtch.option = option;
-
- thread_block_reason(_mk_sp_thread_switch_continue,
- (option == SWITCH_OPTION_DEPRESS)?
- AST_YIELD: AST_NONE);
- }
- else
- mp_enable_preemption();
-
-out:
- if (option == SWITCH_OPTION_WAIT)
- thread_cancel_timer();
- else
- if (option == SWITCH_OPTION_DEPRESS)
- _mk_sp_thread_depress_abort(self, FALSE);
-
- return (KERN_SUCCESS);
-}
-
-/*
- * Depress thread's priority to lowest possible for the specified interval,
- * with a value of zero resulting in no timeout being scheduled.
- */
-void
-_mk_sp_thread_depress_abstime(
- uint64_t interval)
-{
- register thread_t self = current_thread();
- uint64_t deadline;
- spl_t s;
-
- s = splsched();
- wake_lock(self);
- thread_lock(self);
- if (!(self->sched_mode & TH_MODE_ISDEPRESSED)) {
- processor_t myprocessor = self->last_processor;
-
- self->sched_pri = DEPRESSPRI;
- myprocessor->current_pri = self->sched_pri;
- self->sched_mode &= ~TH_MODE_PREEMPT;
- self->sched_mode |= TH_MODE_DEPRESS;
- thread_unlock(self);
-
- if (interval != 0) {
- clock_absolutetime_interval_to_deadline(interval, &deadline);
- if (!timer_call_enter(&self->depress_timer, deadline))
- self->depress_timer_active++;
- }
- }
- else
- thread_unlock(self);
- wake_unlock(self);
- splx(s);
-}
-
-void
-_mk_sp_thread_depress_ms(
- mach_msg_timeout_t interval)
-{
- uint64_t abstime;
-
- clock_interval_to_absolutetime_interval(
- interval, 1000*NSEC_PER_USEC, &abstime);
- _mk_sp_thread_depress_abstime(abstime);
-}
-
-/*
- * Priority depression expiration.
- */
-void
-thread_depress_expire(
- timer_call_param_t p0,
- timer_call_param_t p1)
-{
- thread_t thread = p0;
- spl_t s;
-
- s = splsched();
- wake_lock(thread);
- if (--thread->depress_timer_active == 1) {
- thread_lock(thread);
- thread->sched_mode &= ~TH_MODE_ISDEPRESSED;
- compute_priority(thread, FALSE);
- thread_unlock(thread);
- }
- else
- if (thread->depress_timer_active == 0)
- thread_wakeup_one(&thread->depress_timer_active);
- wake_unlock(thread);
- splx(s);
-}
-
-/*
- * Prematurely abort priority depression if there is one.
- */
-kern_return_t
-_mk_sp_thread_depress_abort(
- register thread_t thread,
- boolean_t abortall)
-{
- kern_return_t result = KERN_NOT_DEPRESSED;
- spl_t s;
-
- s = splsched();
- wake_lock(thread);
- thread_lock(thread);
- if (abortall || !(thread->sched_mode & TH_MODE_POLLDEPRESS)) {
- if (thread->sched_mode & TH_MODE_ISDEPRESSED) {
- thread->sched_mode &= ~TH_MODE_ISDEPRESSED;
- compute_priority(thread, FALSE);
- result = KERN_SUCCESS;
- }
-
- thread_unlock(thread);
-
- if (timer_call_cancel(&thread->depress_timer))
- thread->depress_timer_active--;
- }
- else
- thread_unlock(thread);
- wake_unlock(thread);
- splx(s);
-
- return (result);
-}
-
-void
-_mk_sp_thread_perhaps_yield(
- thread_t self)
-{
- spl_t s;
-
- assert(self == current_thread());
-
- s = splsched();
- if (!(self->sched_mode & (TH_MODE_REALTIME|TH_MODE_TIMESHARE))) {
- extern uint64_t max_poll_computation;
- extern int sched_poll_yield_shift;
- uint64_t abstime, total_computation;
-
- clock_get_uptime(&abstime);
- total_computation = abstime - self->computation_epoch;
- total_computation += self->computation_metered;
- if (total_computation >= max_poll_computation) {
- processor_t myprocessor = current_processor();
- ast_t preempt;
-
- wake_lock(self);
- thread_lock(self);
- if (!(self->sched_mode & TH_MODE_ISDEPRESSED)) {
- self->sched_pri = DEPRESSPRI;
- myprocessor->current_pri = self->sched_pri;
- self->sched_mode &= ~TH_MODE_PREEMPT;
- }
- self->computation_epoch = abstime;
- self->computation_metered = 0;
- self->sched_mode |= TH_MODE_POLLDEPRESS;
- thread_unlock(self);
-
- abstime += (total_computation >> sched_poll_yield_shift);
- if (!timer_call_enter(&self->depress_timer, abstime))
- self->depress_timer_active++;
- wake_unlock(self);
-
- if ((preempt = csw_check(self, myprocessor)) != AST_NONE)
- ast_on(preempt);
- }
- }
- splx(s);
-}
projects / apple / xnu.git / blobdiff