/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2009 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
- *
- * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* Please see the License for the specific language governing rights and
* limitations under the License.
*
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* @OSF_COPYRIGHT@
* Clock primitives.
*/
-#include <cpus.h>
-
#include <mach/boolean.h>
#include <mach/kern_return.h>
#include <mach/machine.h>
#include <kern/host.h>
#include <kern/mach_param.h>
#include <kern/sched.h>
+#include <sys/kdebug.h>
#include <kern/spl.h>
#include <kern/thread.h>
#include <kern/processor.h>
* thread_quantum_expire:
*
* Recalculate the quantum and priority for a thread.
+ *
+ * Called at splsched.
*/
void
timer_call_param_t p0,
timer_call_param_t p1)
{
- register processor_t myprocessor = p0;
- register thread_t thread = p1;
- spl_t s;
+ processor_t processor = p0;
+ thread_t thread = p1;
+ ast_t preempt;
- s = splsched();
thread_lock(thread);
+ /*
+ * We've run up until our quantum expiration, and will (potentially)
+ * continue without re-entering the scheduler, so update this now.
+ */
+ thread->last_run_time = processor->quantum_end;
+
/*
* Check for fail-safe trip.
*/
- if (!(thread->sched_mode & TH_MODE_TIMESHARE)) {
- extern uint64_t max_unsafe_computation;
- uint64_t new_computation;
+ if ((thread->sched_mode == TH_MODE_REALTIME || thread->sched_mode == TH_MODE_FIXED) &&
+ !(thread->sched_flags & TH_SFLAG_PROMOTED) &&
+ !(thread->options & TH_OPT_SYSTEM_CRITICAL)) {
+ uint64_t new_computation;
- new_computation = myprocessor->quantum_end;
- new_computation -= thread->computation_epoch;
- if (new_computation + thread->computation_metered >
- max_unsafe_computation) {
- extern uint32_t sched_safe_duration;
+ new_computation = processor->quantum_end - thread->computation_epoch;
+ new_computation += thread->computation_metered;
+ if (new_computation > max_unsafe_computation) {
- if (thread->sched_mode & TH_MODE_REALTIME) {
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_FAILSAFE)|DBG_FUNC_NONE,
+ (uintptr_t)thread->sched_pri, (uintptr_t)thread->sched_mode, 0, 0, 0);
+
+ if (thread->sched_mode == TH_MODE_REALTIME) {
thread->priority = DEPRESSPRI;
+ }
+
+ thread->saved_mode = thread->sched_mode;
- thread->safe_mode |= TH_MODE_REALTIME;
- thread->sched_mode &= ~TH_MODE_REALTIME;
+ if (SCHED(supports_timeshare_mode)) {
+ sched_share_incr();
+ thread->sched_mode = TH_MODE_TIMESHARE;
+ } else {
+ /* XXX handle fixed->fixed case */
+ thread->sched_mode = TH_MODE_FIXED;
}
- thread->safe_release = sched_tick + sched_safe_duration;
- thread->sched_mode |= (TH_MODE_FAILSAFE|TH_MODE_TIMESHARE);
- thread->sched_mode &= ~TH_MODE_PREEMPT;
+ thread->safe_release = processor->quantum_end + sched_safe_duration;
+ thread->sched_flags |= TH_SFLAG_FAILSAFE;
}
}
/*
* Recompute scheduled priority if appropriate.
*/
- if (thread->sched_stamp != sched_tick)
- update_priority(thread);
+ if (SCHED(can_update_priority)(thread))
+ SCHED(update_priority)(thread);
else
- if (thread->sched_mode & TH_MODE_TIMESHARE) {
- thread_timer_delta(thread);
- thread->sched_usage += thread->sched_delta;
- thread->sched_delta = 0;
+ SCHED(lightweight_update_priority)(thread);
+
+ SCHED(quantum_expire)(thread);
+
+ processor->current_pri = thread->sched_pri;
+ processor->current_thmode = thread->sched_mode;
+
+ /*
+ * This quantum is up, give this thread another.
+ */
+ if (first_timeslice(processor))
+ processor->timeslice--;
+
+ thread_quantum_init(thread);
+ thread->last_quantum_refill_time = processor->quantum_end;
+
+ processor->quantum_end += thread->current_quantum;
+ timer_call_enter1(&processor->quantum_timer,
+ thread, processor->quantum_end, 0);
+
+ /*
+ * Context switch check.
+ */
+ if ((preempt = csw_check(processor)) != AST_NONE)
+ ast_on(preempt);
+ else {
+ processor_set_t pset = processor->processor_set;
+
+ pset_lock(pset);
+
+ pset_pri_hint(pset, processor, processor->current_pri);
+ pset_count_hint(pset, processor, SCHED(processor_runq_count)(processor));
+
+ pset_unlock(pset);
+ }
+
+ thread_unlock(thread);
+}
+
+#if defined(CONFIG_SCHED_TRADITIONAL)
+
+void
+sched_traditional_quantum_expire(thread_t thread __unused)
+{
+ /*
+ * No special behavior when a timeshare, fixed, or realtime thread
+ * uses up its entire quantum
+ */
+}
+void
+lightweight_update_priority(thread_t thread)
+{
+ if (thread->sched_mode == TH_MODE_TIMESHARE) {
+ register uint32_t delta;
+
+ thread_timer_delta(thread, delta);
+
+ /*
+ * Accumulate timesharing usage only
+ * during contention for processor
+ * resources.
+ */
+ if (thread->pri_shift < INT8_MAX)
+ thread->sched_usage += delta;
+
+ thread->cpu_delta += delta;
+
/*
* Adjust the scheduled priority if
* the thread has not been promoted
* and is not depressed.
*/
- if ( !(thread->sched_mode & TH_MODE_PROMOTED) &&
- !(thread->sched_mode & TH_MODE_ISDEPRESSED) )
+ if ( !(thread->sched_flags & TH_SFLAG_PROMOTED) &&
+ !(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) )
compute_my_priority(thread);
+ }
+}
+
+/*
+ * Define shifts for simulating (5/8) ** n
+ *
+ * Shift structures for holding update shifts. Actual computation
+ * is usage = (usage >> shift1) +/- (usage >> abs(shift2)) where the
+ * +/- is determined by the sign of shift 2.
+ */
+struct shift_data {
+ int shift1;
+ int shift2;
+};
+
+#define SCHED_DECAY_TICKS 32
+static struct shift_data sched_decay_shifts[SCHED_DECAY_TICKS] = {
+ {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 the timesharing priority based upon usage and load.
+ */
+#ifdef CONFIG_EMBEDDED
+
+#define do_priority_computation(thread, pri) \
+ MACRO_BEGIN \
+ (pri) = (thread)->priority /* start with base priority */ \
+ - ((thread)->sched_usage >> (thread)->pri_shift); \
+ if ((pri) < MAXPRI_THROTTLE) { \
+ if ((thread)->task->max_priority > MAXPRI_THROTTLE) \
+ (pri) = MAXPRI_THROTTLE; \
+ else \
+ if ((pri) < MINPRI_USER) \
+ (pri) = MINPRI_USER; \
+ } else \
+ if ((pri) > MAXPRI_KERNEL) \
+ (pri) = MAXPRI_KERNEL; \
+ MACRO_END
+
+#else
+
+#define do_priority_computation(thread, pri) \
+ MACRO_BEGIN \
+ (pri) = (thread)->priority /* start with base priority */ \
+ - ((thread)->sched_usage >> (thread)->pri_shift); \
+ if ((pri) < MINPRI_USER) \
+ (pri) = MINPRI_USER; \
+ else \
+ if ((pri) > MAXPRI_KERNEL) \
+ (pri) = MAXPRI_KERNEL; \
+ MACRO_END
+
+#endif /* defined(CONFIG_SCHED_TRADITIONAL) */
+
+#endif
+
+/*
+ * set_priority:
+ *
+ * Set the base priority of the thread
+ * and reset its scheduled priority.
+ *
+ * Called with the thread locked.
+ */
+void
+set_priority(
+ register thread_t thread,
+ register int priority)
+{
+ thread->priority = priority;
+ SCHED(compute_priority)(thread, FALSE);
+}
+
+#if defined(CONFIG_SCHED_TRADITIONAL)
+
+/*
+ * compute_priority:
+ *
+ * Reset the scheduled priority of the thread
+ * according to its base priority if the
+ * thread has not been promoted or depressed.
+ *
+ * Called with the thread locked.
+ */
+void
+compute_priority(
+ register thread_t thread,
+ boolean_t override_depress)
+{
+ register int priority;
+
+ if ( !(thread->sched_flags & TH_SFLAG_PROMOTED) &&
+ (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) ||
+ 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:
+ *
+ * Reset the scheduled priority for
+ * a timesharing thread.
+ *
+ * Only for use on the current thread
+ * if timesharing and not depressed.
+ *
+ * Called with the thread locked.
+ */
+void
+compute_my_priority(
+ register thread_t thread)
+{
+ register int priority;
+
+ do_priority_computation(thread, priority);
+ assert(thread->runq == PROCESSOR_NULL);
+ thread->sched_pri = priority;
+}
+
+/*
+ * can_update_priority
+ *
+ * Make sure we don't do re-dispatches more frequently than a scheduler tick.
+ *
+ * Called with the thread locked.
+ */
+boolean_t
+can_update_priority(
+ thread_t thread)
+{
+ if (sched_tick == thread->sched_stamp)
+ return (FALSE);
+ else
+ return (TRUE);
+}
+
+/*
+ * update_priority
+ *
+ * Perform housekeeping operations driven by scheduler tick.
+ *
+ * Called with the thread locked.
+ */
+void
+update_priority(
+ register thread_t thread)
+{
+ register unsigned ticks;
+ register uint32_t delta;
+
+ ticks = sched_tick - thread->sched_stamp;
+ assert(ticks != 0);
+ thread->sched_stamp += ticks;
+ thread->pri_shift = sched_pri_shift;
+
+ /*
+ * Gather cpu usage data.
+ */
+ thread_timer_delta(thread, delta);
+ if (ticks < SCHED_DECAY_TICKS) {
+ register struct shift_data *shiftp;
+
+ /*
+ * Accumulate timesharing usage only
+ * during contention for processor
+ * resources.
+ */
+ if (thread->pri_shift < INT8_MAX)
+ thread->sched_usage += delta;
+
+ thread->cpu_usage += delta + thread->cpu_delta;
+ thread->cpu_delta = 0;
+
+ shiftp = &sched_decay_shifts[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));
+ }
+ }
+ else {
+ thread->cpu_usage = thread->cpu_delta = 0;
+ thread->sched_usage = 0;
}
/*
- * This quantum is up, give this thread another.
+ * Check for fail-safe release.
*/
- if (first_quantum(myprocessor))
- myprocessor->slice_quanta--;
+ if ( (thread->sched_flags & TH_SFLAG_FAILSAFE) &&
+ mach_absolute_time() >= thread->safe_release ) {
+ if (thread->saved_mode != TH_MODE_TIMESHARE) {
+ if (thread->saved_mode == TH_MODE_REALTIME) {
+ thread->priority = BASEPRI_RTQUEUES;
+ }
- thread->current_quantum = (thread->sched_mode & TH_MODE_REALTIME)?
- thread->realtime.computation: std_quantum;
- myprocessor->quantum_end += thread->current_quantum;
- timer_call_enter1(&myprocessor->quantum_timer,
- thread, myprocessor->quantum_end);
+ thread->sched_mode = thread->saved_mode;
+ thread->saved_mode = TH_MODE_NONE;
- thread_unlock(thread);
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN)
+ sched_share_decr();
+
+ if (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK))
+ set_sched_pri(thread, thread->priority);
+ }
+
+ thread->sched_flags &= ~TH_SFLAG_FAILSAFE;
+ }
/*
- * Check for and schedule ast if needed.
+ * Recompute scheduled priority if appropriate.
*/
- ast_check(myprocessor);
+ if ( (thread->sched_mode == TH_MODE_TIMESHARE) &&
+ !(thread->sched_flags & TH_SFLAG_PROMOTED) &&
+ !(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) ) {
+ register int new_pri;
+
+ do_priority_computation(thread, new_pri);
+ if (new_pri != thread->sched_pri) {
+ boolean_t removed = thread_run_queue_remove(thread);
- splx(s);
+ thread->sched_pri = new_pri;
+ if (removed)
+ thread_setrun(thread, SCHED_TAILQ);
+ }
+ }
+
+ return;
}
+
+#endif /* CONFIG_SCHED_TRADITIONAL */
projects / apple / xnu.git / blobdiff