/*
- * 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_FREE_COPYRIGHT@
*/
#include <debug.h>
-#include <cpus.h>
#include <mach_kdb.h>
-#include <simple_clock.h>
#include <ddb/db_output.h>
+
+#include <mach/mach_types.h>
#include <mach/machine.h>
+#include <mach/policy.h>
+#include <mach/sync_policy.h>
+
#include <machine/machine_routines.h>
#include <machine/sched_param.h>
-#include <kern/ast.h>
+#include <machine/machine_cpu.h>
+
+#include <kern/kern_types.h>
#include <kern/clock.h>
#include <kern/counters.h>
#include <kern/cpu_number.h>
#include <kern/cpu_data.h>
-#include <kern/etap_macros.h>
+#include <kern/debug.h>
#include <kern/lock.h>
#include <kern/macro_help.h>
#include <kern/machine.h>
#include <kern/syscall_subr.h>
#include <kern/task.h>
#include <kern/thread.h>
-#include <kern/thread_swap.h>
+#include <kern/wait_queue.h>
+
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
-#include <mach/policy.h>
-#include <mach/sync_policy.h>
-#include <kern/mk_sp.h> /*** ??? fix so this can be removed ***/
+
#include <sys/kdebug.h>
+#include <kern/pms.h>
+
+struct run_queue rt_runq;
+#define RT_RUNQ ((processor_t)-1)
+decl_simple_lock_data(static,rt_lock);
+
#define DEFAULT_PREEMPTION_RATE 100 /* (1/s) */
int default_preemption_rate = DEFAULT_PREEMPTION_RATE;
#define SCHED_POLL_YIELD_SHIFT 4 /* 1/16 */
int sched_poll_yield_shift = SCHED_POLL_YIELD_SHIFT;
-uint32_t std_quantum_us;
-
uint64_t max_unsafe_computation;
uint32_t sched_safe_duration;
uint64_t max_poll_computation;
uint32_t std_quantum;
uint32_t min_std_quantum;
+uint32_t std_quantum_us;
+
uint32_t max_rt_quantum;
uint32_t min_rt_quantum;
-static uint32_t sched_tick_interval;
+uint32_t sched_cswtime;
unsigned sched_tick;
+uint32_t sched_tick_interval;
+
+uint32_t sched_pri_shift = INT8_MAX;
+uint32_t sched_fixed_shift;
-#if SIMPLE_CLOCK
-int sched_usec;
-#endif /* SIMPLE_CLOCK */
+uint32_t sched_run_count, sched_share_count;
+uint32_t sched_load_average, sched_mach_factor;
/* Forwards */
-void wait_queues_init(void);
+void wait_queues_init(void) __attribute__((section("__TEXT, initcode")));
+
+static void load_shift_init(void) __attribute__((section("__TEXT, initcode")));
+static void preempt_pri_init(void) __attribute__((section("__TEXT, initcode")));
+
+static thread_t run_queue_dequeue(
+ run_queue_t runq,
+ integer_t options);
+
+static thread_t thread_select_idle(
+ thread_t thread,
+ processor_t processor);
+
+static thread_t processor_idle(
+ thread_t thread,
+ processor_t processor);
-static thread_t choose_thread(
- processor_set_t pset,
+static thread_t steal_thread(
+ processor_set_t pset);
+
+static thread_t steal_processor_thread(
processor_t processor);
-static void do_thread_scan(void);
+static void thread_update_scan(void);
+
+#if DEBUG
+extern int debug_task;
+#define TLOG(a, fmt, args...) if(debug_task & a) kprintf(fmt, ## args)
+#else
+#define TLOG(a, fmt, args...) do {} while (0)
+#endif
#if DEBUG
static
#endif /*DEBUG*/
-
/*
* State machine
*
#define wait_hash(event) \
((((int)(event) < 0)? ~(int)(event): (int)(event)) % NUMQUEUES)
+int8_t sched_load_shifts[NRQS];
+int sched_preempt_pri[NRQBM];
+
void
sched_init(void)
{
(1 << SCHED_TICK_SHIFT);
wait_queues_init();
- pset_sys_bootstrap(); /* initialize processor mgmt. */
+ load_shift_init();
+ preempt_pri_init();
+ simple_lock_init(&rt_lock, 0);
+ run_queue_init(&rt_runq);
sched_tick = 0;
-#if SIMPLE_CLOCK
- sched_usec = 0;
-#endif /* SIMPLE_CLOCK */
ast_init();
}
void
sched_timebase_init(void)
{
- uint64_t abstime;
+ uint64_t abstime;
+ uint32_t shift;
+ /* standard timeslicing quantum */
clock_interval_to_absolutetime_interval(
std_quantum_us, NSEC_PER_USEC, &abstime);
assert((abstime >> 32) == 0 && (uint32_t)abstime != 0);
std_quantum = abstime;
- /* 250 us */
+ /* smallest remaining quantum (250 us) */
clock_interval_to_absolutetime_interval(250, NSEC_PER_USEC, &abstime);
assert((abstime >> 32) == 0 && (uint32_t)abstime != 0);
min_std_quantum = abstime;
- /* 50 us */
+ /* smallest rt computaton (50 us) */
clock_interval_to_absolutetime_interval(50, NSEC_PER_USEC, &abstime);
assert((abstime >> 32) == 0 && (uint32_t)abstime != 0);
min_rt_quantum = abstime;
- /* 50 ms */
+ /* maximum rt computation (50 ms) */
clock_interval_to_absolutetime_interval(
50, 1000*NSEC_PER_USEC, &abstime);
assert((abstime >> 32) == 0 && (uint32_t)abstime != 0);
max_rt_quantum = abstime;
- clock_interval_to_absolutetime_interval(1000 >> SCHED_TICK_SHIFT,
- USEC_PER_SEC, &abstime);
+ /* scheduler tick interval */
+ clock_interval_to_absolutetime_interval(USEC_PER_SEC >> SCHED_TICK_SHIFT,
+ NSEC_PER_USEC, &abstime);
assert((abstime >> 32) == 0 && (uint32_t)abstime != 0);
sched_tick_interval = abstime;
+ /*
+ * Compute conversion factor from usage to
+ * timesharing priorities with 5/8 ** n aging.
+ */
+ abstime = (abstime * 5) / 3;
+ for (shift = 0; abstime > BASEPRI_DEFAULT; ++shift)
+ abstime >>= 1;
+ sched_fixed_shift = shift;
+
max_unsafe_computation = max_unsafe_quanta * std_quantum;
max_poll_computation = max_poll_quanta * std_quantum;
}
}
}
+/*
+ * Set up values for timeshare
+ * loading factors.
+ */
+static void
+load_shift_init(void)
+{
+ int8_t k, *p = sched_load_shifts;
+ uint32_t i, j;
+
+ *p++ = INT8_MIN; *p++ = 0;
+
+ for (i = j = 2, k = 1; i < NRQS; ++k) {
+ for (j <<= 1; i < j; ++i)
+ *p++ = k;
+ }
+}
+
+static void
+preempt_pri_init(void)
+{
+ int i, *p = sched_preempt_pri;
+
+ for (i = BASEPRI_FOREGROUND + 1; i < MINPRI_KERNEL; ++i)
+ setbit(i, p);
+
+ for (i = BASEPRI_PREEMPT; i <= MAXPRI; ++i)
+ setbit(i, p);
+}
+
/*
* Thread wait timer expiration.
*/
void
thread_timer_expire(
- timer_call_param_t p0,
- timer_call_param_t p1)
+ void *p0,
+ __unused void *p1)
{
thread_t thread = p0;
spl_t s;
s = splsched();
thread_lock(thread);
- if (--thread->wait_timer_active == 1) {
+ if (--thread->wait_timer_active == 0) {
if (thread->wait_timer_is_set) {
thread->wait_timer_is_set = FALSE;
clear_wait_internal(thread, THREAD_TIMED_OUT);
thread_lock(thread);
if ((thread->state & TH_WAIT) != 0) {
clock_interval_to_deadline(interval, scale_factor, &deadline);
- timer_call_enter(&thread->wait_timer, deadline);
- assert(!thread->wait_timer_is_set);
- thread->wait_timer_active++;
+ if (!timer_call_enter(&thread->wait_timer, deadline))
+ thread->wait_timer_active++;
thread->wait_timer_is_set = TRUE;
}
thread_unlock(thread);
s = splsched();
thread_lock(thread);
if ((thread->state & TH_WAIT) != 0) {
- timer_call_enter(&thread->wait_timer, deadline);
- assert(!thread->wait_timer_is_set);
- thread->wait_timer_active++;
+ if (!timer_call_enter(&thread->wait_timer, deadline))
+ thread->wait_timer_active++;
thread->wait_timer_is_set = TRUE;
}
thread_unlock(thread);
}
/*
- * Set up thread timeout element when thread is created.
+ * thread_unblock:
+ *
+ * Unblock thread on wake up.
+ *
+ * Returns TRUE if the thread is still running.
+ *
+ * Thread must be locked.
*/
-void
-thread_timer_setup(
- thread_t thread)
+boolean_t
+thread_unblock(
+ thread_t thread,
+ wait_result_t wresult)
{
- extern void thread_depress_expire(
- timer_call_param_t p0,
- timer_call_param_t p1);
-
- timer_call_setup(&thread->wait_timer, thread_timer_expire, thread);
- thread->wait_timer_is_set = FALSE;
- thread->wait_timer_active = 1;
-
- timer_call_setup(&thread->depress_timer, thread_depress_expire, thread);
- thread->depress_timer_active = 1;
+ boolean_t result = FALSE;
- thread->ref_count++;
-}
-
-void
-thread_timer_terminate(void)
-{
- thread_t thread = current_thread();
- wait_result_t res;
- spl_t s;
+ /*
+ * Set wait_result.
+ */
+ thread->wait_result = wresult;
- s = splsched();
- thread_lock(thread);
+ /*
+ * Cancel pending wait timer.
+ */
if (thread->wait_timer_is_set) {
if (timer_call_cancel(&thread->wait_timer))
thread->wait_timer_active--;
thread->wait_timer_is_set = FALSE;
}
- thread->wait_timer_active--;
+ /*
+ * Update scheduling state: not waiting,
+ * set running.
+ */
+ thread->state &= ~(TH_WAIT|TH_UNINT);
- while (thread->wait_timer_active > 0) {
- thread_unlock(thread);
- splx(s);
+ if (!(thread->state & TH_RUN)) {
+ thread->state |= TH_RUN;
- delay(1);
+ (*thread->sched_call)(SCHED_CALL_UNBLOCK, thread);
- s = splsched();
- thread_lock(thread);
+ /*
+ * Update run counts.
+ */
+ sched_run_incr();
+ if (thread->sched_mode & TH_MODE_TIMESHARE)
+ sched_share_incr();
}
+ else {
+ /*
+ * Signal if idling on another processor.
+ */
+ if (thread->state & TH_IDLE) {
+ processor_t processor = thread->last_processor;
- thread->depress_timer_active--;
-
- while (thread->depress_timer_active > 0) {
- thread_unlock(thread);
- splx(s);
+ if (processor != current_processor())
+ machine_signal_idle(processor);
+ }
- delay(1);
+ result = TRUE;
+ }
- s = splsched();
- thread_lock(thread);
+ /*
+ * Calculate deadline for real-time threads.
+ */
+ if (thread->sched_mode & TH_MODE_REALTIME) {
+ thread->realtime.deadline = mach_absolute_time();
+ thread->realtime.deadline += thread->realtime.constraint;
}
- thread_unlock(thread);
- splx(s);
+ /*
+ * Clear old quantum, fail-safe computation, etc.
+ */
+ thread->current_quantum = 0;
+ thread->computation_metered = 0;
+ thread->reason = AST_NONE;
- thread_deallocate(thread);
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED,MACH_MAKE_RUNNABLE) | DBG_FUNC_NONE,
+ (int)thread, (int)thread->sched_pri, 0, 0, 0);
+
+ return (result);
}
/*
- * Routine: thread_go_locked
+ * Routine: thread_go
* Purpose:
- * Start a thread running.
+ * Unblock and dispatch thread.
* Conditions:
* thread lock held, IPC locks may be held.
* thread must have been pulled from wait queue under same lock hold.
* KERN_NOT_WAITING - Thread was not waiting
*/
kern_return_t
-thread_go_locked(
+thread_go(
thread_t thread,
wait_result_t wresult)
{
assert(thread->wait_queue == WAIT_QUEUE_NULL);
if ((thread->state & (TH_WAIT|TH_TERMINATE)) == TH_WAIT) {
- thread_roust_t roust_hint;
-
- thread->state &= ~(TH_WAIT|TH_UNINT);
- _mk_sp_thread_unblock(thread);
-
- roust_hint = thread->roust;
- thread->roust = NULL;
- if ( roust_hint != NULL &&
- (*roust_hint)(thread, wresult) ) {
- if (thread->wait_timer_is_set) {
- if (timer_call_cancel(&thread->wait_timer))
- thread->wait_timer_active--;
- thread->wait_timer_is_set = FALSE;
- }
-
- return (KERN_SUCCESS);
- }
-
- thread->wait_result = wresult;
-
- if (!(thread->state & TH_RUN)) {
- thread->state |= TH_RUN;
-
- if (thread->active_callout)
- call_thread_unblock();
-
- pset_run_incr(thread->processor_set);
- if (thread->sched_mode & TH_MODE_TIMESHARE)
- pset_share_incr(thread->processor_set);
-
+ if (!thread_unblock(thread, wresult))
thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
- }
-
- KERNEL_DEBUG_CONSTANT(
- MACHDBG_CODE(DBG_MACH_SCHED,MACH_MAKE_RUNNABLE) | DBG_FUNC_NONE,
- (int)thread, (int)thread->sched_pri, 0, 0, 0);
return (KERN_SUCCESS);
}
* are OK, we have to honor mask settings (outer-scoped code may
* not be able to handle aborts at the moment).
*/
- if (interruptible > thread->interrupt_level)
- interruptible = thread->interrupt_level;
+ if (interruptible > (thread->options & TH_OPT_INTMASK))
+ interruptible = thread->options & TH_OPT_INTMASK;
at_safe_point = (interruptible == THREAD_ABORTSAFE);
if ( interruptible == THREAD_UNINT ||
- !(thread->state & TH_ABORT) ||
+ !(thread->sched_mode & TH_MODE_ABORT) ||
(!at_safe_point &&
- (thread->state & TH_ABORT_SAFELY)) ) {
+ (thread->sched_mode & TH_MODE_ABORTSAFELY))) {
thread->state |= (interruptible) ? TH_WAIT : (TH_WAIT | TH_UNINT);
thread->at_safe_point = at_safe_point;
- thread->sleep_stamp = sched_tick;
return (thread->wait_result = THREAD_WAITING);
}
else
- if (thread->state & TH_ABORT_SAFELY)
- thread->state &= ~(TH_ABORT|TH_ABORT_SAFELY);
+ if (thread->sched_mode & TH_MODE_ABORTSAFELY)
+ thread->sched_mode &= ~TH_MODE_ISABORTED;
return (thread->wait_result = THREAD_INTERRUPTED);
}
wait_interrupt_t new_level)
{
thread_t thread = current_thread();
- wait_interrupt_t result = thread->interrupt_level;
-
- thread->interrupt_level = new_level;
- return result;
-}
-
-/*
- * Routine: assert_wait_timeout
- * Purpose:
- * Assert that the thread intends to block,
- * waiting for a timeout (no user known event).
- */
-unsigned int assert_wait_timeout_event;
+ wait_interrupt_t result = thread->options & TH_OPT_INTMASK;
-wait_result_t
-assert_wait_timeout(
- mach_msg_timeout_t msecs,
- wait_interrupt_t interruptible)
-{
- wait_result_t res;
+ thread->options = (thread->options & ~TH_OPT_INTMASK) | (new_level & TH_OPT_INTMASK);
- res = assert_wait((event_t)&assert_wait_timeout_event, interruptible);
- if (res == THREAD_WAITING)
- thread_set_timer(msecs, 1000*NSEC_PER_USEC);
- return res;
+ return result;
}
/*
{
thread_t thread;
- extern unsigned int debug_mode;
#if DEBUG
if(debug_mode) return TRUE; /* Always succeed in debug mode */
index = wait_hash(event);
wq = &wait_queues[index];
- return wait_queue_assert_wait(wq, event, interruptible);
+ return wait_queue_assert_wait(wq, event, interruptible, 0);
}
-__private_extern__
-wait_queue_t
-wait_event_wait_queue(
- event_t event)
+wait_result_t
+assert_wait_timeout(
+ event_t event,
+ wait_interrupt_t interruptible,
+ uint32_t interval,
+ uint32_t scale_factor)
{
+ thread_t thread = current_thread();
+ wait_result_t wresult;
+ wait_queue_t wqueue;
+ uint64_t deadline;
+ spl_t s;
+
assert(event != NO_EVENT);
+ wqueue = &wait_queues[wait_hash(event)];
- return (&wait_queues[wait_hash(event)]);
+ s = splsched();
+ wait_queue_lock(wqueue);
+ thread_lock(thread);
+
+ clock_interval_to_deadline(interval, scale_factor, &deadline);
+ wresult = wait_queue_assert_wait64_locked(wqueue, (uint32_t)event,
+ interruptible, deadline, thread);
+
+ thread_unlock(thread);
+ wait_queue_unlock(wqueue);
+ splx(s);
+
+ return (wresult);
}
wait_result_t
-assert_wait_prim(
+assert_wait_deadline(
event_t event,
- thread_roust_t roust_hint,
- uint64_t deadline,
- wait_interrupt_t interruptible)
+ wait_interrupt_t interruptible,
+ uint64_t deadline)
{
thread_t thread = current_thread();
- wait_result_t wresult;
- wait_queue_t wq;
+ wait_result_t wresult;
+ wait_queue_t wqueue;
spl_t s;
assert(event != NO_EVENT);
-
- wq = &wait_queues[wait_hash(event)];
+ wqueue = &wait_queues[wait_hash(event)];
s = splsched();
- wait_queue_lock(wq);
+ wait_queue_lock(wqueue);
thread_lock(thread);
- wresult = wait_queue_assert_wait64_locked(wq, (uint32_t)event,
- interruptible, thread);
- if (wresult == THREAD_WAITING) {
- if (roust_hint != NULL)
- thread->roust = roust_hint;
-
- if (deadline != 0) {
- timer_call_enter(&thread->wait_timer, deadline);
- assert(!thread->wait_timer_is_set);
- thread->wait_timer_active++;
- thread->wait_timer_is_set = TRUE;
- }
- }
+ wresult = wait_queue_assert_wait64_locked(wqueue, (uint32_t)event,
+ interruptible, deadline, thread);
thread_unlock(thread);
- wait_queue_unlock(wq);
+ wait_queue_unlock(wqueue);
splx(s);
return (wresult);
* Cause the current thread to wait until the specified event
* (or deadline) occurs. The specified mutex is unlocked before
* releasing the cpu. The mutex will be re-acquired before returning.
- *
- * JMM - Add hint to make sure mutex is available before rousting
*/
wait_result_t
thread_sleep_mutex_deadline(
{
wait_result_t res;
- res = assert_wait(event, interruptible);
+ res = assert_wait_deadline(event, interruptible, deadline);
if (res == THREAD_WAITING) {
mutex_unlock(mutex);
- thread_set_timer_deadline(deadline);
res = thread_block(THREAD_CONTINUE_NULL);
- if (res != THREAD_TIMED_OUT)
- thread_cancel_timer();
mutex_lock(mutex);
}
return res;
* Cause the current thread to wait until the specified event
* occurs. The specified (write) lock is unlocked before releasing
* the cpu. The (write) lock will be re-acquired before returning.
- *
- * JMM - Add hint to make sure mutex is available before rousting
*/
wait_result_t
thread_sleep_lock_write(
return res;
}
-
-/*
- * thread_sleep_funnel:
- *
- * Cause the current thread to wait until the specified event
- * occurs. If the thread is funnelled, the funnel will be released
- * before giving up the cpu. The funnel will be re-acquired before returning.
- *
- * JMM - Right now the funnel is dropped and re-acquired inside
- * thread_block(). At some point, this may give thread_block() a hint.
- */
-wait_result_t
-thread_sleep_funnel(
- event_t event,
- wait_interrupt_t interruptible)
-{
- wait_result_t res;
-
- res = assert_wait(event, interruptible);
- if (res == THREAD_WAITING) {
- res = thread_block(THREAD_CONTINUE_NULL);
- }
- return res;
-}
-
/*
- * thread_[un]stop(thread)
- * Once a thread has blocked interruptibly (via assert_wait) prevent
- * it from running until thread_unstop.
+ * thread_stop:
*
- * If someone else has already stopped the thread, wait for the
- * stop to be cleared, and then stop it again.
+ * Force a preemption point for a thread and wait
+ * for it to stop running. Arbitrates access among
+ * multiple stop requests. (released by unstop)
*
- * Return FALSE if interrupted.
+ * The thread must enter a wait state and stop via a
+ * separate means.
*
- * NOTE: thread_hold/thread_suspend should be called on the activation
- * before calling thread_stop. TH_SUSP is only recognized when
- * a thread blocks and only prevents clear_wait/thread_wakeup
- * from restarting an interruptible wait. The wake_active flag is
- * used to indicate that someone is waiting on the thread.
+ * Returns FALSE if interrupted.
*/
boolean_t
thread_stop(
- thread_t thread)
+ thread_t thread)
{
- spl_t s = splsched();
+ wait_result_t wresult;
+ spl_t s = splsched();
wake_lock(thread);
+ thread_lock(thread);
while (thread->state & TH_SUSP) {
- wait_result_t result;
-
thread->wake_active = TRUE;
- result = assert_wait(&thread->wake_active, THREAD_ABORTSAFE);
+ thread_unlock(thread);
+
+ wresult = assert_wait(&thread->wake_active, THREAD_ABORTSAFE);
wake_unlock(thread);
splx(s);
- if (result == THREAD_WAITING)
- result = thread_block(THREAD_CONTINUE_NULL);
+ if (wresult == THREAD_WAITING)
+ wresult = thread_block(THREAD_CONTINUE_NULL);
- if (result != THREAD_AWAKENED)
+ if (wresult != THREAD_AWAKENED)
return (FALSE);
s = splsched();
wake_lock(thread);
+ thread_lock(thread);
}
- thread_lock(thread);
thread->state |= TH_SUSP;
while (thread->state & TH_RUN) {
- wait_result_t result;
processor_t processor = thread->last_processor;
- if ( processor != PROCESSOR_NULL &&
- processor->state == PROCESSOR_RUNNING &&
- processor->active_thread == thread )
+ if (processor != PROCESSOR_NULL && processor->active_thread == thread)
cause_ast_check(processor);
- thread_unlock(thread);
thread->wake_active = TRUE;
- result = assert_wait(&thread->wake_active, THREAD_ABORTSAFE);
+ thread_unlock(thread);
+
+ wresult = assert_wait(&thread->wake_active, THREAD_ABORTSAFE);
wake_unlock(thread);
splx(s);
- if (result == THREAD_WAITING)
- result = thread_block(THREAD_CONTINUE_NULL);
+ if (wresult == THREAD_WAITING)
+ wresult = thread_block(THREAD_CONTINUE_NULL);
- if (result != THREAD_AWAKENED) {
+ if (wresult != THREAD_AWAKENED) {
thread_unstop(thread);
return (FALSE);
}
}
/*
- * Clear TH_SUSP and if the thread has been stopped and is now runnable,
- * put it back on the run queue.
+ * thread_unstop:
+ *
+ * Release a previous stop request and set
+ * the thread running if appropriate.
+ *
+ * Use only after a successful stop operation.
*/
void
thread_unstop(
if ((thread->state & (TH_RUN|TH_WAIT|TH_SUSP)) == TH_SUSP) {
thread->state &= ~TH_SUSP;
- thread->state |= TH_RUN;
-
- _mk_sp_thread_unblock(thread);
-
- pset_run_incr(thread->processor_set);
- if (thread->sched_mode & TH_MODE_TIMESHARE)
- pset_share_incr(thread->processor_set);
+ thread_unblock(thread, THREAD_AWAKENED);
thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
-
- KERNEL_DEBUG_CONSTANT(
- MACHDBG_CODE(DBG_MACH_SCHED,MACH_MAKE_RUNNABLE) | DBG_FUNC_NONE,
- (int)thread, (int)thread->sched_pri, 0, 0, 0);
}
else
if (thread->state & TH_SUSP) {
if (thread->wake_active) {
thread->wake_active = FALSE;
thread_unlock(thread);
+
+ thread_wakeup(&thread->wake_active);
wake_unlock(thread);
splx(s);
- thread_wakeup(&thread->wake_active);
return;
}
}
}
/*
- * Wait for the thread's RUN bit to clear
+ * thread_wait:
+ *
+ * Wait for a thread to stop running. (non-interruptible)
+ *
*/
-boolean_t
+void
thread_wait(
- thread_t thread)
+ thread_t thread)
{
- spl_t s = splsched();
+ wait_result_t wresult;
+ spl_t s = splsched();
wake_lock(thread);
thread_lock(thread);
while (thread->state & TH_RUN) {
- wait_result_t result;
processor_t processor = thread->last_processor;
- if ( processor != PROCESSOR_NULL &&
- processor->state == PROCESSOR_RUNNING &&
- processor->active_thread == thread )
+ if (processor != PROCESSOR_NULL && processor->active_thread == thread)
cause_ast_check(processor);
- thread_unlock(thread);
thread->wake_active = TRUE;
- result = assert_wait(&thread->wake_active, THREAD_ABORTSAFE);
+ thread_unlock(thread);
+
+ wresult = assert_wait(&thread->wake_active, THREAD_UNINT);
wake_unlock(thread);
splx(s);
- if (result == THREAD_WAITING)
- result = thread_block(THREAD_CONTINUE_NULL);
-
- if (result != THREAD_AWAKENED)
- return (FALSE);
+ if (wresult == THREAD_WAITING)
+ thread_block(THREAD_CONTINUE_NULL);
s = splsched();
wake_lock(thread);
thread_unlock(thread);
wake_unlock(thread);
splx(s);
-
- return (TRUE);
}
/*
}
}
- return (thread_go_locked(thread, wresult));
+ return (thread_go(thread, wresult));
} while (--i > 0);
- panic("clear_wait_internal: deadlock: thread=0x%x, wq=0x%x, cpu=%d\n",
+ panic("clear_wait_internal: deadlock: thread=%p, wq=%p, cpu=%d\n",
thread, wq, cpu_number());
return (KERN_FAILURE);
/*
* thread_bind:
*
- * Force a thread to execute on the specified processor.
+ * Force the current thread to execute on the specified processor.
*
* Returns the previous binding. PROCESSOR_NULL means
* not bound.
*/
processor_t
thread_bind(
- register thread_t thread,
- processor_t processor)
+ processor_t processor)
{
+ thread_t self = current_thread();
processor_t prev;
- run_queue_t runq = RUN_QUEUE_NULL;
spl_t s;
s = splsched();
- thread_lock(thread);
- prev = thread->bound_processor;
- if (prev != PROCESSOR_NULL)
- runq = run_queue_remove(thread);
+ thread_lock(self);
- thread->bound_processor = processor;
+ prev = self->bound_processor;
+ self->bound_processor = processor;
- if (runq != RUN_QUEUE_NULL)
- thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
- thread_unlock(thread);
+ thread_unlock(self);
splx(s);
return (prev);
}
-struct {
- uint32_t idle_pset_last,
- idle_pset_any,
- idle_bound;
-
- uint32_t pset_self,
- pset_last,
- pset_other,
- bound_self,
- bound_other;
-
- uint32_t realtime_self,
- realtime_last,
- realtime_other;
-
- uint32_t missed_realtime,
- missed_other;
-} dispatch_counts;
-
/*
- * Select a thread for the current processor to run.
+ * thread_select:
+ *
+ * Select a new thread for the current processor to execute.
*
* May select the current thread, which must be locked.
*/
-thread_t
+static thread_t
thread_select(
- register processor_t processor)
+ thread_t thread,
+ processor_t processor)
{
- register thread_t thread;
- processor_set_t pset;
- boolean_t other_runnable;
+ processor_set_t pset = processor->processor_set;
+ thread_t new_thread = THREAD_NULL;
+ boolean_t other_runnable, inactive_state;
- /*
- * Check for other non-idle runnable threads.
- */
- pset = processor->processor_set;
- thread = processor->active_thread;
+ do {
+ /*
+ * Update the priority.
+ */
+ if (thread->sched_stamp != sched_tick)
+ update_priority(thread);
- /* Update the thread's priority */
- if (thread->sched_stamp != sched_tick)
- update_priority(thread);
+ processor->current_pri = thread->sched_pri;
- processor->current_pri = thread->sched_pri;
+ pset_lock(pset);
+
+ inactive_state = processor->state != PROCESSOR_SHUTDOWN && machine_cpu_is_inactive(processor->cpu_num);
+
+ simple_lock(&rt_lock);
- simple_lock(&pset->sched_lock);
-
- other_runnable = processor->runq.count > 0 || pset->runq.count > 0;
-
- if ( thread->state == TH_RUN &&
- thread->processor_set == pset &&
- (thread->bound_processor == PROCESSOR_NULL ||
- thread->bound_processor == processor) ) {
- if ( thread->sched_pri >= BASEPRI_RTQUEUES &&
- first_timeslice(processor) ) {
- if (pset->runq.highq >= BASEPRI_RTQUEUES) {
- register run_queue_t runq = &pset->runq;
- register queue_t q;
-
- q = runq->queues + runq->highq;
- if (((thread_t)q->next)->realtime.deadline <
- processor->deadline) {
- thread = (thread_t)q->next;
- ((queue_entry_t)thread)->next->prev = q;
- q->next = ((queue_entry_t)thread)->next;
- thread->runq = RUN_QUEUE_NULL;
- assert(thread->sched_mode & TH_MODE_PREEMPT);
- runq->count--; runq->urgency--;
- if (queue_empty(q)) {
- if (runq->highq != IDLEPRI)
- clrbit(MAXPRI - runq->highq, runq->bitmap);
- runq->highq = MAXPRI - ffsbit(runq->bitmap);
+ /*
+ * Check for other runnable threads.
+ */
+ other_runnable = processor->runq.count > 0 || rt_runq.count > 0;
+
+ /*
+ * Test to see if the current thread should continue
+ * to run on this processor. Must be runnable, and not
+ * bound to a different processor, nor be in the wrong
+ * processor set.
+ */
+ if ( thread->state == TH_RUN &&
+ (thread->bound_processor == PROCESSOR_NULL ||
+ thread->bound_processor == processor) &&
+ (thread->affinity_set == AFFINITY_SET_NULL ||
+ thread->affinity_set->aset_pset == pset) ) {
+ if ( thread->sched_pri >= BASEPRI_RTQUEUES &&
+ first_timeslice(processor) ) {
+ if (rt_runq.highq >= BASEPRI_RTQUEUES) {
+ register run_queue_t runq = &rt_runq;
+ register queue_t q;
+
+ q = runq->queues + runq->highq;
+ if (((thread_t)q->next)->realtime.deadline <
+ processor->deadline) {
+ thread = (thread_t)q->next;
+ ((queue_entry_t)thread)->next->prev = q;
+ q->next = ((queue_entry_t)thread)->next;
+ thread->runq = PROCESSOR_NULL;
+ runq->count--; runq->urgency--;
+ assert(runq->urgency >= 0);
+ if (queue_empty(q)) {
+ if (runq->highq != IDLEPRI)
+ clrbit(MAXPRI - runq->highq, runq->bitmap);
+ runq->highq = MAXPRI - ffsbit(runq->bitmap);
+ }
}
}
+
+ simple_unlock(&rt_lock);
+
+ processor->deadline = thread->realtime.deadline;
+
+ pset_unlock(pset);
+
+ return (thread);
}
- processor->deadline = thread->realtime.deadline;
+ if (!inactive_state &&
+ (!other_runnable ||
+ (processor->runq.highq < thread->sched_pri &&
+ rt_runq.highq < thread->sched_pri)) ) {
- simple_unlock(&pset->sched_lock);
+ simple_unlock(&rt_lock);
- return (thread);
- }
+ /* I am the highest priority runnable (non-idle) thread */
- if ( (!other_runnable ||
- (processor->runq.highq < thread->sched_pri &&
- pset->runq.highq < thread->sched_pri)) ) {
+ pset_pri_hint(pset, processor, processor->current_pri);
- /* I am the highest priority runnable (non-idle) thread */
+ pset_count_hint(pset, processor, processor->runq.count);
- processor->deadline = UINT64_MAX;
+ processor->deadline = UINT64_MAX;
- simple_unlock(&pset->sched_lock);
+ pset_unlock(pset);
- return (thread);
+ return (thread);
+ }
}
- }
- if (other_runnable)
- thread = choose_thread(pset, processor);
- else {
- /*
+ if (other_runnable) {
+ if (processor->runq.count > 0 && processor->runq.highq >= rt_runq.highq) {
+ simple_unlock(&rt_lock);
+
+ thread = run_queue_dequeue(&processor->runq, SCHED_HEADQ);
+
+ if (!inactive_state) {
+ pset_pri_hint(pset, processor, thread->sched_pri);
+
+ pset_count_hint(pset, processor, processor->runq.count);
+ }
+
+ processor->deadline = UINT64_MAX;
+ pset_unlock(pset);
+
+ return (thread);
+ }
+
+ thread = run_queue_dequeue(&rt_runq, SCHED_HEADQ);
+ simple_unlock(&rt_lock);
+
+ processor->deadline = thread->realtime.deadline;
+ pset_unlock(pset);
+
+ return (thread);
+ }
+
+ simple_unlock(&rt_lock);
+
+ processor->deadline = UINT64_MAX;
+
+ if (inactive_state) {
+ if (processor->state == PROCESSOR_RUNNING)
+ remqueue(&pset->active_queue, (queue_entry_t)processor);
+ else
+ if (processor->state == PROCESSOR_IDLE)
+ remqueue(&pset->idle_queue, (queue_entry_t)processor);
+
+ processor->state = PROCESSOR_INACTIVE;
+
+ pset_unlock(pset);
+
+ return (processor->idle_thread);
+ }
+
+ /*
+ * No runnable threads, attempt to steal
+ * from other processors.
+ */
+ new_thread = steal_thread(pset);
+ if (new_thread != THREAD_NULL)
+ return (new_thread);
+
+ /*
+ * If other threads have appeared, shortcut
+ * around again.
+ */
+ if (processor->runq.count > 0 || rt_runq.count > 0)
+ continue;
+
+ pset_lock(pset);
+
+ /*
* Nothing is runnable, so set this processor idle if it
- * was running. Return its idle thread.
+ * was running.
*/
if (processor->state == PROCESSOR_RUNNING) {
remqueue(&pset->active_queue, (queue_entry_t)processor);
processor->state = PROCESSOR_IDLE;
- enqueue_tail(&pset->idle_queue, (queue_entry_t)processor);
- pset->idle_count++;
+ enqueue_head(&pset->idle_queue, (queue_entry_t)processor);
+ pset->low_pri = pset->low_count = processor;
}
- processor->deadline = UINT64_MAX;
+ pset_unlock(pset);
+
+ /*
+ * Choose idle thread if fast idle is not possible.
+ */
+ if ((thread->state & (TH_IDLE|TH_TERMINATE|TH_SUSP)) || !(thread->state & TH_WAIT) || thread->wake_active)
+ return (processor->idle_thread);
+
+ /*
+ * Perform idling activities directly without a
+ * context switch. Return dispatched thread,
+ * else check again for a runnable thread.
+ */
+ new_thread = thread_select_idle(thread, processor);
+
+ } while (new_thread == THREAD_NULL);
+
+ return (new_thread);
+}
+
+/*
+ * thread_select_idle:
+ *
+ * Idle the processor using the current thread context.
+ *
+ * Called with thread locked, then dropped and relocked.
+ */
+static thread_t
+thread_select_idle(
+ thread_t thread,
+ processor_t processor)
+{
+ thread_t new_thread;
+
+ if (thread->sched_mode & TH_MODE_TIMESHARE)
+ sched_share_decr();
+ sched_run_decr();
+
+ thread->state |= TH_IDLE;
+ processor->current_pri = IDLEPRI;
+
+ thread_unlock(thread);
+
+ /*
+ * Switch execution timing to processor idle thread.
+ */
+ processor->last_dispatch = mach_absolute_time();
+ thread_timer_event(processor->last_dispatch, &processor->idle_thread->system_timer);
+ PROCESSOR_DATA(processor, kernel_timer) = &processor->idle_thread->system_timer;
+
+ /*
+ * Cancel the quantum timer while idling.
+ */
+ timer_call_cancel(&processor->quantum_timer);
+ processor->timeslice = 0;
- thread = processor->idle_thread;
+ (*thread->sched_call)(SCHED_CALL_BLOCK, thread);
+
+ /*
+ * Enable interrupts and perform idling activities. No
+ * preemption due to TH_IDLE being set.
+ */
+ spllo(); new_thread = processor_idle(thread, processor);
+
+ /*
+ * Return at splsched.
+ */
+ (*thread->sched_call)(SCHED_CALL_UNBLOCK, thread);
+
+ thread_lock(thread);
+
+ /*
+ * If awakened, switch to thread timer and start a new quantum.
+ * Otherwise skip; we will context switch to another thread or return here.
+ */
+ if (!(thread->state & TH_WAIT)) {
+ processor->last_dispatch = mach_absolute_time();
+ thread_timer_event(processor->last_dispatch, &thread->system_timer);
+ PROCESSOR_DATA(processor, kernel_timer) = &thread->system_timer;
+
+ thread_quantum_init(thread);
+
+ processor->quantum_end = processor->last_dispatch + thread->current_quantum;
+ timer_call_enter1(&processor->quantum_timer, thread, processor->quantum_end);
+ processor->timeslice = 1;
+
+ thread->computation_epoch = processor->last_dispatch;
}
- simple_unlock(&pset->sched_lock);
+ thread->state &= ~TH_IDLE;
- return (thread);
+ sched_run_incr();
+ if (thread->sched_mode & TH_MODE_TIMESHARE)
+ sched_share_incr();
+
+ return (new_thread);
}
/*
* Perform a context switch and start executing the new thread.
*
- * If continuation is non-zero, resume the old (current) thread
- * next by executing at continuation on a new stack, in lieu
- * of returning.
- *
- * Returns TRUE if the hand-off succeeds.
+ * Returns FALSE on failure, and the thread is re-dispatched.
*
* Called at splsched.
*/
} \
MACRO_END
-static thread_t
-__current_thread(void)
-{
- return (current_thread());
-}
-
-boolean_t
+static boolean_t
thread_invoke(
- register thread_t old_thread,
- register thread_t new_thread,
- int reason,
- thread_continue_t old_cont)
+ register thread_t self,
+ register thread_t thread,
+ ast_t reason)
{
- thread_continue_t new_cont;
+ thread_continue_t continuation = self->continuation;
+ void *parameter = self->parameter;
processor_t processor;
if (get_preemption_level() != 0)
panic("thread_invoke: preemption_level %d\n",
- get_preemption_level());
+ get_preemption_level());
+
+ assert(self == current_thread());
/*
* Mark thread interruptible.
*/
- thread_lock(new_thread);
- new_thread->state &= ~TH_UNINT;
-
- assert(thread_runnable(new_thread));
+ thread_lock(thread);
+ thread->state &= ~TH_UNINT;
- assert(old_thread->continuation == NULL);
+#if DEBUG
+ assert(thread_runnable(thread));
+#endif
/*
* Allow time constraint threads to hang onto
* a stack.
*/
- if ( (old_thread->sched_mode & TH_MODE_REALTIME) &&
- !old_thread->reserved_stack ) {
- old_thread->reserved_stack = old_thread->kernel_stack;
- }
+ if ((self->sched_mode & TH_MODE_REALTIME) && !self->reserved_stack)
+ self->reserved_stack = self->kernel_stack;
- if (old_cont != NULL) {
- if (new_thread->state & TH_STACK_HANDOFF) {
+ if (continuation != NULL) {
+ if (!thread->kernel_stack) {
/*
- * If the old thread is using a privileged stack,
+ * If we are using a privileged stack,
* check to see whether we can exchange it with
- * that of the new thread.
+ * that of the other thread.
*/
- if ( old_thread->kernel_stack == old_thread->reserved_stack &&
- !new_thread->reserved_stack)
+ if (self->kernel_stack == self->reserved_stack && !thread->reserved_stack)
goto need_stack;
- new_thread->state &= ~TH_STACK_HANDOFF;
- new_cont = new_thread->continuation;
- new_thread->continuation = NULL;
-
/*
- * Set up ast context of new thread and switch
- * to its timer.
+ * Context switch by performing a stack handoff.
*/
- processor = current_processor();
- processor->active_thread = new_thread;
- processor->current_pri = new_thread->sched_pri;
- new_thread->last_processor = processor;
- ast_context(new_thread->top_act, processor->slot_num);
- timer_switch(&new_thread->system_timer);
- thread_unlock(new_thread);
-
- current_task()->csw++;
-
- old_thread->reason = reason;
- old_thread->continuation = old_cont;
-
- _mk_sp_thread_done(old_thread, new_thread, processor);
-
- machine_stack_handoff(old_thread, new_thread);
-
- _mk_sp_thread_begin(new_thread, processor);
-
- wake_lock(old_thread);
- thread_lock(old_thread);
-
- /*
- * Inline thread_dispatch but
- * don't free stack.
- */
-
- switch (old_thread->state & (TH_RUN|TH_WAIT|TH_UNINT|TH_IDLE)) {
-
- case TH_RUN | TH_UNINT:
- case TH_RUN:
- /*
- * Still running, put back
- * onto a run queue.
- */
- old_thread->state |= TH_STACK_HANDOFF;
- _mk_sp_thread_dispatch(old_thread);
-
- thread_unlock(old_thread);
- wake_unlock(old_thread);
- break;
+ continuation = thread->continuation;
+ parameter = thread->parameter;
- case TH_RUN | TH_WAIT | TH_UNINT:
- case TH_RUN | TH_WAIT:
- {
- boolean_t term, wake, callout;
-
- /*
- * Waiting.
- */
- old_thread->sleep_stamp = sched_tick;
- old_thread->state |= TH_STACK_HANDOFF;
- old_thread->state &= ~TH_RUN;
-
- term = (old_thread->state & TH_TERMINATE)? TRUE: FALSE;
- callout = old_thread->active_callout;
- wake = old_thread->wake_active;
- old_thread->wake_active = FALSE;
-
- if (old_thread->sched_mode & TH_MODE_TIMESHARE)
- pset_share_decr(old_thread->processor_set);
- pset_run_decr(old_thread->processor_set);
-
- thread_unlock(old_thread);
- wake_unlock(old_thread);
+ processor = current_processor();
+ processor->active_thread = thread;
+ processor->current_pri = thread->sched_pri;
+ if (thread->last_processor != processor && thread->last_processor != NULL) {
+ if (thread->last_processor->processor_set != processor->processor_set)
+ thread->ps_switch++;
+ thread->p_switch++;
+ }
+ thread->last_processor = processor;
+ thread->c_switch++;
+ ast_context(thread);
+ thread_unlock(thread);
- if (callout)
- call_thread_block();
+ self->reason = reason;
- if (wake)
- thread_wakeup((event_t)&old_thread->wake_active);
+ processor->last_dispatch = mach_absolute_time();
+ thread_timer_event(processor->last_dispatch, &thread->system_timer);
+ PROCESSOR_DATA(processor, kernel_timer) = &thread->system_timer;
+
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_STACK_HANDOFF)|DBG_FUNC_NONE,
+ self->reason, (int)thread, self->sched_pri, thread->sched_pri, 0);
- if (term)
- thread_reaper_enqueue(old_thread);
- break;
- }
+TLOG(1, "thread_invoke: calling machine_stack_handoff\n");
+ machine_stack_handoff(self, thread);
- case TH_RUN | TH_IDLE:
- /*
- * The idle threads don't go
- * onto a run queue.
- */
- old_thread->state |= TH_STACK_HANDOFF;
- thread_unlock(old_thread);
- wake_unlock(old_thread);
- break;
+ thread_dispatch(self, thread);
- default:
- panic("thread_invoke: state 0x%x\n", old_thread->state);
- }
+ thread->continuation = thread->parameter = NULL;
- counter_always(c_thread_invoke_hits++);
+ counter(c_thread_invoke_hits++);
- funnel_refunnel_check(new_thread, 2);
+ funnel_refunnel_check(thread, 2);
(void) spllo();
- assert(new_cont);
- call_continuation(new_cont);
+ assert(continuation);
+ call_continuation(continuation, parameter, thread->wait_result);
/*NOTREACHED*/
- return (TRUE);
- }
- else
- if (new_thread->state & TH_STACK_ALLOC) {
- /*
- * Waiting for a stack
- */
- counter_always(c_thread_invoke_misses++);
- thread_unlock(new_thread);
- return (FALSE);
}
- else
- if (new_thread == old_thread) {
+ else if (thread == self) {
/* same thread but with continuation */
+ ast_context(self);
counter(++c_thread_invoke_same);
- thread_unlock(new_thread);
+ thread_unlock(self);
- funnel_refunnel_check(new_thread, 3);
+ self->continuation = self->parameter = NULL;
+
+ funnel_refunnel_check(self, 3);
(void) spllo();
- call_continuation(old_cont);
+ call_continuation(continuation, parameter, self->wait_result);
/*NOTREACHED*/
}
}
else {
/*
- * Check that the new thread has a stack
+ * Check that the other thread has a stack
*/
- if (new_thread->state & TH_STACK_HANDOFF) {
+ if (!thread->kernel_stack) {
need_stack:
- if (!stack_alloc_try(new_thread, thread_continue)) {
- counter_always(c_thread_invoke_misses++);
- thread_swapin(new_thread);
+ if (!stack_alloc_try(thread)) {
+ counter(c_thread_invoke_misses++);
+ thread_unlock(thread);
+ thread_stack_enqueue(thread);
return (FALSE);
}
-
- new_thread->state &= ~TH_STACK_HANDOFF;
}
- else
- if (new_thread->state & TH_STACK_ALLOC) {
- /*
- * Waiting for a stack
- */
- counter_always(c_thread_invoke_misses++);
- thread_unlock(new_thread);
- return (FALSE);
- }
- else
- if (old_thread == new_thread) {
+ else if (thread == self) {
+ ast_context(self);
counter(++c_thread_invoke_same);
- thread_unlock(new_thread);
+ thread_unlock(self);
return (TRUE);
}
}
/*
- * Set up ast context of new thread and switch to its timer.
+ * Context switch by full context save.
*/
processor = current_processor();
- processor->active_thread = new_thread;
- processor->current_pri = new_thread->sched_pri;
- new_thread->last_processor = processor;
- ast_context(new_thread->top_act, processor->slot_num);
- timer_switch(&new_thread->system_timer);
- assert(thread_runnable(new_thread));
- thread_unlock(new_thread);
+ processor->active_thread = thread;
+ processor->current_pri = thread->sched_pri;
+ if (thread->last_processor != processor && thread->last_processor != NULL) {
+ if (thread->last_processor->processor_set != processor->processor_set)
+ thread->ps_switch++;
+ thread->p_switch++;
+ }
+ thread->last_processor = processor;
+ thread->c_switch++;
+ ast_context(thread);
+ thread_unlock(thread);
+
+ counter(c_thread_invoke_csw++);
- counter_always(c_thread_invoke_csw++);
- current_task()->csw++;
+ assert(self->runq == PROCESSOR_NULL);
+ self->reason = reason;
- assert(old_thread->runq == RUN_QUEUE_NULL);
- old_thread->reason = reason;
- old_thread->continuation = old_cont;
+ processor->last_dispatch = mach_absolute_time();
+ thread_timer_event(processor->last_dispatch, &thread->system_timer);
+ PROCESSOR_DATA(processor, kernel_timer) = &thread->system_timer;
- _mk_sp_thread_done(old_thread, new_thread, processor);
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED,MACH_SCHED) | DBG_FUNC_NONE,
+ (int)self->reason, (int)thread, self->sched_pri, thread->sched_pri, 0);
/*
- * Here is where we actually change register context,
- * and address space if required. Note that control
- * will not return here immediately.
+ * This is where we actually switch register context,
+ * and address space if required. We will next run
+ * as a result of a subsequent context switch.
*/
- old_thread = machine_switch_context(old_thread, old_cont, new_thread);
-
- /* Now on new thread's stack. Set a local variable to refer to it. */
- new_thread = __current_thread();
- assert(old_thread != new_thread);
-
- assert(thread_runnable(new_thread));
- _mk_sp_thread_begin(new_thread, new_thread->last_processor);
+ thread = machine_switch_context(self, continuation, thread);
+TLOG(1,"thread_invoke: returning machine_switch_context: self %p continuation %p thread %p\n", self, continuation, thread);
/*
- * We're back. Now old_thread is the thread that resumed
- * us, and we have to dispatch it.
+ * We have been resumed and are set to run.
*/
- thread_dispatch(old_thread);
+ thread_dispatch(thread, self);
- if (old_cont) {
- funnel_refunnel_check(new_thread, 3);
+ if (continuation) {
+ self->continuation = self->parameter = NULL;
+
+ funnel_refunnel_check(self, 3);
(void) spllo();
- call_continuation(old_cont);
+ call_continuation(continuation, parameter, self->wait_result);
/*NOTREACHED*/
}
}
/*
- * thread_continue:
+ * thread_dispatch:
*
- * Called at splsched when a thread first receives
- * a new stack after a continuation.
+ * Handle threads at context switch. Re-dispatch other thread
+ * if still running, otherwise update run state and perform
+ * special actions. Update quantum for other thread and begin
+ * the quantum for ourselves.
+ *
+ * Called at splsched.
*/
void
-thread_continue(
- register thread_t old_thread)
+thread_dispatch(
+ thread_t thread,
+ thread_t self)
{
- register thread_t self = current_thread();
- register thread_continue_t continuation;
-
- continuation = self->continuation;
- self->continuation = NULL;
+ processor_t processor = self->last_processor;
- _mk_sp_thread_begin(self, self->last_processor);
-
- /*
- * We must dispatch the old thread and then
- * call the current thread's continuation.
- * There might not be an old thread, if we are
- * the first thread to run on this processor.
- */
- if (old_thread != THREAD_NULL)
- thread_dispatch(old_thread);
+ if (thread != THREAD_NULL) {
+ /*
+ * If blocked at a continuation, discard
+ * the stack.
+ */
+ if (thread->continuation != NULL && thread->kernel_stack != 0)
+ stack_free(thread);
- funnel_refunnel_check(self, 4);
- (void)spllo();
+ if (!(thread->state & TH_IDLE)) {
+ wake_lock(thread);
+ thread_lock(thread);
- call_continuation(continuation);
- /*NOTREACHED*/
+ /*
+ * Compute remainder of current quantum.
+ */
+ if ( first_timeslice(processor) &&
+ processor->quantum_end > processor->last_dispatch )
+ thread->current_quantum = (processor->quantum_end - processor->last_dispatch);
+ else
+ thread->current_quantum = 0;
+
+ if (thread->sched_mode & TH_MODE_REALTIME) {
+ /*
+ * Cancel the deadline if the thread has
+ * consumed the entire quantum.
+ */
+ if (thread->current_quantum == 0) {
+ thread->realtime.deadline = UINT64_MAX;
+ thread->reason |= AST_QUANTUM;
+ }
+ }
+ else {
+ /*
+ * For non-realtime threads treat a tiny
+ * remaining quantum as an expired quantum
+ * but include what's left next time.
+ */
+ if (thread->current_quantum < min_std_quantum) {
+ thread->reason |= AST_QUANTUM;
+ thread->current_quantum += std_quantum;
+ }
+ }
+
+ /*
+ * If we are doing a direct handoff then
+ * take the remainder of the quantum.
+ */
+ if ((thread->reason & (AST_HANDOFF|AST_QUANTUM)) == AST_HANDOFF) {
+ self->current_quantum = thread->current_quantum;
+ thread->reason |= AST_QUANTUM;
+ thread->current_quantum = 0;
+ }
+
+ thread->last_switch = processor->last_dispatch;
+
+ thread->computation_metered += (thread->last_switch - thread->computation_epoch);
+
+ if (!(thread->state & TH_WAIT)) {
+ /*
+ * Still running.
+ */
+ if (thread->reason & AST_QUANTUM)
+ thread_setrun(thread, SCHED_TAILQ);
+ else
+ if (thread->reason & AST_PREEMPT)
+ thread_setrun(thread, SCHED_HEADQ);
+ else
+ thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
+
+ thread->reason = AST_NONE;
+
+ thread_unlock(thread);
+ wake_unlock(thread);
+ }
+ else {
+ /*
+ * Waiting.
+ */
+ thread->state &= ~TH_RUN;
+
+ if (thread->sched_mode & TH_MODE_TIMESHARE)
+ sched_share_decr();
+ sched_run_decr();
+
+ if (thread->wake_active) {
+ thread->wake_active = FALSE;
+ thread_unlock(thread);
+
+ thread_wakeup(&thread->wake_active);
+ }
+ else
+ thread_unlock(thread);
+
+ wake_unlock(thread);
+
+ (*thread->sched_call)(SCHED_CALL_BLOCK, thread);
+
+ if (thread->state & TH_TERMINATE)
+ thread_terminate_enqueue(thread);
+ }
+ }
+ }
+
+ if (!(self->state & TH_IDLE)) {
+ /*
+ * Get a new quantum if none remaining.
+ */
+ if (self->current_quantum == 0)
+ thread_quantum_init(self);
+
+ /*
+ * Set up quantum timer and timeslice.
+ */
+ processor->quantum_end = (processor->last_dispatch + self->current_quantum);
+ timer_call_enter1(&processor->quantum_timer, self, processor->quantum_end);
+
+ processor->timeslice = 1;
+
+ self->last_switch = processor->last_dispatch;
+
+ self->computation_epoch = self->last_switch;
+ }
+ else {
+ timer_call_cancel(&processor->quantum_timer);
+ processor->timeslice = 0;
+ }
}
/*
*/
counter(mach_counter_t c_thread_block_calls = 0;)
-int
+wait_result_t
thread_block_reason(
thread_continue_t continuation,
+ void *parameter,
ast_t reason)
{
- register thread_t thread = current_thread();
+ register thread_t self = current_thread();
register processor_t processor;
register thread_t new_thread;
spl_t s;
counter(++c_thread_block_calls);
- check_simple_locks();
-
s = splsched();
if (!(reason & AST_PREEMPT))
- funnel_release_check(thread, 2);
+ funnel_release_check(self, 2);
processor = current_processor();
/* We're handling all scheduling AST's */
ast_off(AST_SCHEDULING);
- thread_lock(thread);
- new_thread = thread_select(processor);
- assert(new_thread && thread_runnable(new_thread));
- thread_unlock(thread);
- while (!thread_invoke(thread, new_thread, reason, continuation)) {
- thread_lock(thread);
- new_thread = thread_select(processor);
- assert(new_thread && thread_runnable(new_thread));
- thread_unlock(thread);
- }
+ self->continuation = continuation;
+ self->parameter = parameter;
+
+ do {
+ thread_lock(self);
+ new_thread = thread_select(self, processor);
+ thread_unlock(self);
+ } while (!thread_invoke(self, new_thread, reason));
- funnel_refunnel_check(thread, 5);
+ funnel_refunnel_check(self, 5);
splx(s);
- return (thread->wait_result);
+ return (self->wait_result);
}
/*
*
* Block the current thread if a wait has been asserted.
*/
-int
+wait_result_t
thread_block(
thread_continue_t continuation)
{
- return thread_block_reason(continuation, AST_NONE);
+ return thread_block_reason(continuation, NULL, AST_NONE);
+}
+
+wait_result_t
+thread_block_parameter(
+ thread_continue_t continuation,
+ void *parameter)
+{
+ return thread_block_reason(continuation, parameter, AST_NONE);
}
/*
* thread_run:
*
- * Switch directly from the current (old) thread to the
+ * Switch directly from the current thread to the
* new thread, handing off our quantum if appropriate.
*
* New thread must be runnable, and not on a run queue.
*/
int
thread_run(
- thread_t old_thread,
+ thread_t self,
thread_continue_t continuation,
+ void *parameter,
thread_t new_thread)
{
ast_t handoff = AST_HANDOFF;
- assert(old_thread == current_thread());
+ funnel_release_check(self, 3);
- funnel_release_check(old_thread, 3);
+ self->continuation = continuation;
+ self->parameter = parameter;
- while (!thread_invoke(old_thread, new_thread, handoff, continuation)) {
- register processor_t processor = current_processor();
+ while (!thread_invoke(self, new_thread, handoff)) {
+ processor_t processor = current_processor();
- thread_lock(old_thread);
- new_thread = thread_select(processor);
- thread_unlock(old_thread);
+ thread_lock(self);
+ new_thread = thread_select(self, processor);
+ thread_unlock(self);
handoff = AST_NONE;
}
- funnel_refunnel_check(old_thread, 6);
+ funnel_refunnel_check(self, 6);
- return (old_thread->wait_result);
+ return (self->wait_result);
}
/*
- * Dispatches a running thread that is not on a
- * run queue.
+ * thread_continue:
*
- * Called at splsched.
+ * Called at splsched when a thread first receives
+ * a new stack after a continuation.
*/
void
-thread_dispatch(
+thread_continue(
register thread_t thread)
{
- wake_lock(thread);
- thread_lock(thread);
+ register thread_t self = current_thread();
+ register thread_continue_t continuation;
+ register void *parameter;
+
+ continuation = self->continuation;
+ parameter = self->parameter;
- /*
- * If we are discarding the thread's stack, we must do it
- * before the thread has a chance to run.
- */
-#ifndef i386
- if (thread->continuation != NULL) {
- assert((thread->state & TH_STACK_STATE) == 0);
- thread->state |= TH_STACK_HANDOFF;
- stack_free(thread);
+ thread_dispatch(thread, self);
+
+ self->continuation = self->parameter = NULL;
+
+ funnel_refunnel_check(self, 4);
+
+ if (thread != THREAD_NULL)
+ (void)spllo();
+
+ TLOG(1, "thread_continue: calling call_continuation \n");
+ call_continuation(continuation, parameter, self->wait_result);
+ /*NOTREACHED*/
+}
+
+/*
+ * run_queue_init:
+ *
+ * Initialize a run queue before first use.
+ */
+void
+run_queue_init(
+ run_queue_t rq)
+{
+ int i;
+
+ rq->highq = IDLEPRI;
+ for (i = 0; i < NRQBM; i++)
+ rq->bitmap[i] = 0;
+ setbit(MAXPRI - IDLEPRI, rq->bitmap);
+ rq->urgency = rq->count = 0;
+ for (i = 0; i < NRQS; i++)
+ queue_init(&rq->queues[i]);
+}
+
+/*
+ * run_queue_dequeue:
+ *
+ * Perform a dequeue operation on a run queue,
+ * and return the resulting thread.
+ *
+ * The run queue must be locked (see run_queue_remove()
+ * for more info), and not empty.
+ */
+static thread_t
+run_queue_dequeue(
+ run_queue_t rq,
+ integer_t options)
+{
+ thread_t thread;
+ queue_t queue = rq->queues + rq->highq;
+
+ if (options & SCHED_HEADQ) {
+ thread = (thread_t)queue->next;
+ ((queue_entry_t)thread)->next->prev = queue;
+ queue->next = ((queue_entry_t)thread)->next;
+ }
+ else {
+ thread = (thread_t)queue->prev;
+ ((queue_entry_t)thread)->prev->next = queue;
+ queue->prev = ((queue_entry_t)thread)->prev;
}
-#endif
- switch (thread->state & (TH_RUN|TH_WAIT|TH_UNINT|TH_IDLE)) {
+ thread->runq = PROCESSOR_NULL;
+ rq->count--;
+ if (testbit(rq->highq, sched_preempt_pri)) {
+ rq->urgency--; assert(rq->urgency >= 0);
+ }
+ if (queue_empty(queue)) {
+ if (rq->highq != IDLEPRI)
+ clrbit(MAXPRI - rq->highq, rq->bitmap);
+ rq->highq = MAXPRI - ffsbit(rq->bitmap);
+ }
- case TH_RUN | TH_UNINT:
- case TH_RUN:
- /*
- * No reason to stop. Put back on a run queue.
- */
- _mk_sp_thread_dispatch(thread);
- break;
+ return (thread);
+}
- case TH_RUN | TH_WAIT | TH_UNINT:
- case TH_RUN | TH_WAIT:
- {
- boolean_t term, wake, callout;
-
- /*
- * Waiting
- */
- thread->sleep_stamp = sched_tick;
- thread->state &= ~TH_RUN;
+/*
+ * realtime_queue_insert:
+ *
+ * Enqueue a thread for realtime execution.
+ */
+static boolean_t
+realtime_queue_insert(
+ thread_t thread)
+{
+ run_queue_t rq = &rt_runq;
+ queue_t queue = rq->queues + thread->sched_pri;
+ uint64_t deadline = thread->realtime.deadline;
+ boolean_t preempt = FALSE;
- term = (thread->state & TH_TERMINATE)? TRUE: FALSE;
- callout = thread->active_callout;
- wake = thread->wake_active;
- thread->wake_active = FALSE;
+ simple_lock(&rt_lock);
- if (thread->sched_mode & TH_MODE_TIMESHARE)
- pset_share_decr(thread->processor_set);
- pset_run_decr(thread->processor_set);
+ if (queue_empty(queue)) {
+ enqueue_tail(queue, (queue_entry_t)thread);
- thread_unlock(thread);
- wake_unlock(thread);
+ setbit(MAXPRI - thread->sched_pri, rq->bitmap);
+ if (thread->sched_pri > rq->highq)
+ rq->highq = thread->sched_pri;
+ preempt = TRUE;
+ }
+ else {
+ register thread_t entry = (thread_t)queue_first(queue);
- if (callout)
- call_thread_block();
+ while (TRUE) {
+ if ( queue_end(queue, (queue_entry_t)entry) ||
+ deadline < entry->realtime.deadline ) {
+ entry = (thread_t)queue_prev((queue_entry_t)entry);
+ break;
+ }
- if (wake)
- thread_wakeup((event_t)&thread->wake_active);
+ entry = (thread_t)queue_next((queue_entry_t)entry);
+ }
- if (term)
- thread_reaper_enqueue(thread);
+ if ((queue_entry_t)entry == queue)
+ preempt = TRUE;
- return;
+ insque((queue_entry_t)thread, (queue_entry_t)entry);
}
- case TH_RUN | TH_IDLE:
- /*
- * The idle threads don't go
- * onto a run queue.
- */
- break;
+ thread->runq = RT_RUNQ;
+ rq->count++; rq->urgency++;
+
+ simple_unlock(&rt_lock);
- default:
- panic("thread_dispatch: state 0x%x\n", thread->state);
+ return (preempt);
+}
+
+/*
+ * realtime_setrun:
+ *
+ * Dispatch a thread for realtime execution.
+ *
+ * Thread must be locked. Associated pset must
+ * be locked, and is returned unlocked.
+ */
+static void
+realtime_setrun(
+ processor_t processor,
+ thread_t thread)
+{
+ processor_set_t pset = processor->processor_set;
+
+ /*
+ * Dispatch directly onto idle processor.
+ */
+ if (processor->state == PROCESSOR_IDLE) {
+ remqueue(&pset->idle_queue, (queue_entry_t)processor);
+ enqueue_tail(&pset->active_queue, (queue_entry_t)processor);
+
+ processor->next_thread = thread;
+ processor->deadline = thread->realtime.deadline;
+ processor->state = PROCESSOR_DISPATCHING;
+ pset_unlock(pset);
+
+ if (processor != current_processor())
+ machine_signal_idle(processor);
+ return;
}
- thread_unlock(thread);
- wake_unlock(thread);
+ if (realtime_queue_insert(thread)) {
+ if (processor == current_processor())
+ ast_on(AST_PREEMPT | AST_URGENT);
+ else
+ cause_ast_check(processor);
+ }
+
+ pset_unlock(pset);
}
/*
- * Enqueue thread on run queue. Thread must be locked,
- * and not already be on a run queue. Returns TRUE
- * if a preemption is indicated based on the state
+ * processor_enqueue:
+ *
+ * Enqueue thread on a processor run queue. Thread must be locked,
+ * and not already be on a run queue.
+ *
+ * Returns TRUE if a preemption is indicated based on the state
* of the run queue.
*
- * Run queue must be locked, see run_queue_remove()
- * for more info.
+ * The run queue must be locked (see run_queue_remove()
+ * for more info).
*/
static boolean_t
-run_queue_enqueue(
- register run_queue_t rq,
- register thread_t thread,
- integer_t options)
-{
- register int whichq = thread->sched_pri;
- register queue_t queue = &rq->queues[whichq];
- boolean_t result = FALSE;
+processor_enqueue(
+ processor_t processor,
+ thread_t thread,
+ integer_t options)
+{
+ run_queue_t rq = &processor->runq;
+ queue_t queue = rq->queues + thread->sched_pri;
+ boolean_t result = FALSE;
- assert(whichq >= MINPRI && whichq <= MAXPRI);
-
- assert(thread->runq == RUN_QUEUE_NULL);
if (queue_empty(queue)) {
enqueue_tail(queue, (queue_entry_t)thread);
- setbit(MAXPRI - whichq, rq->bitmap);
- if (whichq > rq->highq) {
- rq->highq = whichq;
+ setbit(MAXPRI - thread->sched_pri, rq->bitmap);
+ if (thread->sched_pri > rq->highq) {
+ rq->highq = thread->sched_pri;
result = TRUE;
}
}
else
- if (options & SCHED_HEADQ)
- enqueue_head(queue, (queue_entry_t)thread);
- else
+ if (options & SCHED_TAILQ)
enqueue_tail(queue, (queue_entry_t)thread);
+ else
+ enqueue_head(queue, (queue_entry_t)thread);
- thread->runq = rq;
- if (thread->sched_mode & TH_MODE_PREEMPT)
+ thread->runq = processor;
+ if (testbit(thread->sched_pri, sched_preempt_pri))
rq->urgency++;
rq->count++;
}
/*
- * Enqueue a thread for realtime execution, similar
- * to above. Handles preemption directly.
+ * processor_setrun:
+ *
+ * Dispatch a thread for execution on a
+ * processor.
+ *
+ * Thread must be locked. Associated pset must
+ * be locked, and is returned unlocked.
*/
static void
-realtime_schedule_insert(
- register processor_set_t pset,
- register thread_t thread)
+processor_setrun(
+ processor_t processor,
+ thread_t thread,
+ integer_t options)
{
- register run_queue_t rq = &pset->runq;
- register int whichq = thread->sched_pri;
- register queue_t queue = &rq->queues[whichq];
- uint64_t deadline = thread->realtime.deadline;
- boolean_t try_preempt = FALSE;
+ processor_set_t pset = processor->processor_set;
+ ast_t preempt;
- assert(whichq >= BASEPRI_REALTIME && whichq <= MAXPRI);
+ /*
+ * Dispatch directly onto idle processor.
+ */
+ if (processor->state == PROCESSOR_IDLE) {
+ remqueue(&pset->idle_queue, (queue_entry_t)processor);
+ enqueue_tail(&pset->active_queue, (queue_entry_t)processor);
- assert(thread->runq == RUN_QUEUE_NULL);
- if (queue_empty(queue)) {
- enqueue_tail(queue, (queue_entry_t)thread);
+ processor->next_thread = thread;
+ processor->deadline = UINT64_MAX;
+ processor->state = PROCESSOR_DISPATCHING;
+ pset_unlock(pset);
- setbit(MAXPRI - whichq, rq->bitmap);
- if (whichq > rq->highq)
- rq->highq = whichq;
- try_preempt = TRUE;
+ if (processor != current_processor())
+ machine_signal_idle(processor);
+ return;
}
- else {
- register thread_t entry = (thread_t)queue_first(queue);
- while (TRUE) {
- if ( queue_end(queue, (queue_entry_t)entry) ||
- deadline < entry->realtime.deadline ) {
- entry = (thread_t)queue_prev((queue_entry_t)entry);
- break;
- }
+ /*
+ * Set preemption mode.
+ */
+ if (testbit(thread->sched_pri, sched_preempt_pri))
+ preempt = (AST_PREEMPT | AST_URGENT);
+ else
+ if (thread->sched_mode & TH_MODE_TIMESHARE && thread->sched_pri < thread->priority)
+ preempt = AST_NONE;
+ else
+ preempt = (options & SCHED_PREEMPT)? AST_PREEMPT: AST_NONE;
- entry = (thread_t)queue_next((queue_entry_t)entry);
+ if (!processor_enqueue(processor, thread, options))
+ preempt = AST_NONE;
+
+ if (preempt != AST_NONE) {
+ if (processor == current_processor()) {
+ if (csw_check(processor) != AST_NONE)
+ ast_on(preempt);
}
+ else
+ if ( (processor->state == PROCESSOR_RUNNING ||
+ processor->state == PROCESSOR_SHUTDOWN) &&
+ thread->sched_pri >= processor->current_pri ) {
+ cause_ast_check(processor);
+ }
+ }
+ else
+ if ( processor->state == PROCESSOR_SHUTDOWN &&
+ thread->sched_pri >= processor->current_pri ) {
+ cause_ast_check(processor);
+ }
- if ((queue_entry_t)entry == queue)
- try_preempt = TRUE;
+ pset_unlock(pset);
+}
- insque((queue_entry_t)thread, (queue_entry_t)entry);
+#define next_pset(p) (((p)->pset_list != PROCESSOR_SET_NULL)? (p)->pset_list: (p)->node->psets)
+
+/*
+ * choose_next_pset:
+ *
+ * Return the next sibling pset containing
+ * available processors.
+ *
+ * Returns the original pset if none other is
+ * suitable.
+ */
+static processor_set_t
+choose_next_pset(
+ processor_set_t pset)
+{
+ processor_set_t nset = pset;
+
+ do {
+ nset = next_pset(nset);
+ } while (nset->processor_count < 1 && nset != pset);
+
+ return (nset);
+}
+
+/*
+ * choose_processor:
+ *
+ * Choose a processor for the thread, beginning at
+ * the pset.
+ *
+ * Returns a processor, possibly from a different pset.
+ *
+ * The thread must be locked. The pset must be locked,
+ * and the resulting pset is locked on return.
+ */
+static processor_t
+choose_processor(
+ processor_set_t pset,
+ thread_t thread)
+{
+ processor_set_t nset, cset = pset;
+ processor_t processor = thread->last_processor;
+
+ /*
+ * Prefer the last processor, when appropriate.
+ */
+ if (processor != PROCESSOR_NULL) {
+ if (processor->processor_set != pset || processor->state == PROCESSOR_INACTIVE ||
+ processor->state == PROCESSOR_SHUTDOWN || processor->state == PROCESSOR_OFF_LINE)
+ processor = PROCESSOR_NULL;
+ else
+ if (processor->state == PROCESSOR_IDLE || ( thread->sched_pri > BASEPRI_DEFAULT && processor->current_pri < thread->sched_pri))
+ return (processor);
}
- thread->runq = rq;
- assert(thread->sched_mode & TH_MODE_PREEMPT);
- rq->count++; rq->urgency++;
+ /*
+ * Iterate through the processor sets to locate
+ * an appropriate processor.
+ */
+ do {
+ /*
+ * Choose an idle processor.
+ */
+ if (!queue_empty(&cset->idle_queue))
+ return ((processor_t)queue_first(&cset->idle_queue));
- if (try_preempt) {
- register processor_t processor;
+ if (thread->sched_pri >= BASEPRI_RTQUEUES) {
+ /*
+ * For an RT thread, iterate through active processors, first fit.
+ */
+ processor = (processor_t)queue_first(&cset->active_queue);
+ while (!queue_end(&cset->active_queue, (queue_entry_t)processor)) {
+ if (thread->sched_pri > processor->current_pri ||
+ thread->realtime.deadline < processor->deadline)
+ return (processor);
- processor = current_processor();
- if ( pset == processor->processor_set &&
- (thread->sched_pri > processor->current_pri ||
- deadline < processor->deadline ) ) {
- dispatch_counts.realtime_self++;
- simple_unlock(&pset->sched_lock);
+ processor = (processor_t)queue_next((queue_entry_t)processor);
+ }
- ast_on(AST_PREEMPT | AST_URGENT);
- return;
+ processor = PROCESSOR_NULL;
}
+ else {
+ /*
+ * Check any hinted processors in the processor set if available.
+ */
+ if (cset->low_pri != PROCESSOR_NULL && cset->low_pri->state != PROCESSOR_INACTIVE &&
+ cset->low_pri->state != PROCESSOR_SHUTDOWN && cset->low_pri->state != PROCESSOR_OFF_LINE &&
+ (processor == PROCESSOR_NULL ||
+ (thread->sched_pri > BASEPRI_DEFAULT && cset->low_pri->current_pri < thread->sched_pri))) {
+ processor = cset->low_pri;
+ }
+ else
+ if (cset->low_count != PROCESSOR_NULL && cset->low_count->state != PROCESSOR_INACTIVE &&
+ cset->low_count->state != PROCESSOR_SHUTDOWN && cset->low_count->state != PROCESSOR_OFF_LINE &&
+ (processor == PROCESSOR_NULL ||
+ ( thread->sched_pri <= BASEPRI_DEFAULT && cset->low_count->runq.count < processor->runq.count))) {
+ processor = cset->low_count;
+ }
- if ( pset->processor_count > 1 ||
- pset != processor->processor_set ) {
- processor_t myprocessor, lastprocessor;
- queue_entry_t next;
-
- myprocessor = processor;
- processor = thread->last_processor;
- if ( processor != myprocessor &&
- processor != PROCESSOR_NULL &&
- processor->processor_set == pset &&
- processor->state == PROCESSOR_RUNNING &&
- (thread->sched_pri > processor->current_pri ||
- deadline < processor->deadline ) ) {
- dispatch_counts.realtime_last++;
- cause_ast_check(processor);
- simple_unlock(&pset->sched_lock);
- return;
+ /*
+ * Otherwise, choose an available processor in the set.
+ */
+ if (processor == PROCESSOR_NULL) {
+ processor = (processor_t)dequeue_head(&cset->active_queue);
+ if (processor != PROCESSOR_NULL)
+ enqueue_tail(&cset->active_queue, (queue_entry_t)processor);
}
+ }
- lastprocessor = processor;
- queue = &pset->active_queue;
- processor = (processor_t)queue_first(queue);
- while (!queue_end(queue, (queue_entry_t)processor)) {
- next = queue_next((queue_entry_t)processor);
-
- if ( processor != myprocessor &&
- processor != lastprocessor &&
- (thread->sched_pri > processor->current_pri ||
- deadline < processor->deadline ) ) {
- if (!queue_end(queue, next)) {
- remqueue(queue, (queue_entry_t)processor);
- enqueue_tail(queue, (queue_entry_t)processor);
- }
- dispatch_counts.realtime_other++;
- cause_ast_check(processor);
- simple_unlock(&pset->sched_lock);
- return;
- }
+ /*
+ * Move onto the next processor set.
+ */
+ nset = next_pset(cset);
+
+ if (nset != pset) {
+ pset_unlock(cset);
+
+ cset = nset;
+ pset_lock(cset);
+ }
+ } while (nset != pset);
- processor = (processor_t)next;
+ /*
+ * Make sure that we pick a running processor,
+ * and that the correct processor set is locked.
+ */
+ do {
+ /*
+ * If we haven't been able to choose a processor,
+ * pick the boot processor and return it.
+ */
+ if (processor == PROCESSOR_NULL) {
+ processor = master_processor;
+
+ /*
+ * Check that the correct processor set is
+ * returned locked.
+ */
+ if (cset != processor->processor_set) {
+ pset_unlock(cset);
+
+ cset = processor->processor_set;
+ pset_lock(cset);
}
+
+ return (processor);
}
- }
- simple_unlock(&pset->sched_lock);
+ /*
+ * Check that the processor set for the chosen
+ * processor is locked.
+ */
+ if (cset != processor->processor_set) {
+ pset_unlock(cset);
+
+ cset = processor->processor_set;
+ pset_lock(cset);
+ }
+
+ /*
+ * We must verify that the chosen processor is still available.
+ */
+ if (processor->state == PROCESSOR_INACTIVE ||
+ processor->state == PROCESSOR_SHUTDOWN || processor->state == PROCESSOR_OFF_LINE)
+ processor = PROCESSOR_NULL;
+ } while (processor == PROCESSOR_NULL);
+
+ return (processor);
}
/*
* thread_setrun:
*
- * Dispatch thread for execution, directly onto an idle
- * processor if possible. Else put on appropriate run
- * queue. (local if bound, else processor set)
+ * Dispatch thread for execution, onto an idle
+ * processor or run queue, and signal a preemption
+ * as appropriate.
*
* Thread must be locked.
*/
void
thread_setrun(
- register thread_t new_thread,
- integer_t options)
+ thread_t thread,
+ integer_t options)
{
- register processor_t processor;
- register processor_set_t pset;
- register thread_t thread;
- ast_t preempt = (options & SCHED_PREEMPT)?
- AST_PREEMPT: AST_NONE;
+ processor_t processor;
+ processor_set_t pset;
- assert(thread_runnable(new_thread));
+#if DEBUG
+ assert(thread_runnable(thread));
+#endif
/*
* Update priority if needed.
*/
- if (new_thread->sched_stamp != sched_tick)
- update_priority(new_thread);
-
- /*
- * Check for urgent preemption.
- */
- if (new_thread->sched_mode & TH_MODE_PREEMPT)
- preempt = (AST_PREEMPT | AST_URGENT);
-
- assert(new_thread->runq == RUN_QUEUE_NULL);
+ if (thread->sched_stamp != sched_tick)
+ update_priority(thread);
- if ((processor = new_thread->bound_processor) == PROCESSOR_NULL) {
- /*
- * First try to dispatch on
- * the last processor.
- */
- pset = new_thread->processor_set;
- processor = new_thread->last_processor;
- if ( pset->processor_count > 1 &&
- processor != PROCESSOR_NULL &&
- processor->state == PROCESSOR_IDLE ) {
- processor_lock(processor);
- simple_lock(&pset->sched_lock);
- if ( processor->processor_set == pset &&
- processor->state == PROCESSOR_IDLE ) {
- remqueue(&pset->idle_queue, (queue_entry_t)processor);
- pset->idle_count--;
- processor->next_thread = new_thread;
- if (new_thread->sched_pri >= BASEPRI_RTQUEUES)
- processor->deadline = new_thread->realtime.deadline;
- else
- processor->deadline = UINT64_MAX;
- processor->state = PROCESSOR_DISPATCHING;
- dispatch_counts.idle_pset_last++;
- simple_unlock(&pset->sched_lock);
- processor_unlock(processor);
- if (processor != current_processor())
- machine_signal_idle(processor);
- return;
- }
- processor_unlock(processor);
- }
- else
- simple_lock(&pset->sched_lock);
+ assert(thread->runq == PROCESSOR_NULL);
+ if (thread->bound_processor == PROCESSOR_NULL) {
/*
- * Next pick any idle processor
- * in the processor set.
+ * Unbound case.
*/
- if (pset->idle_count > 0) {
- processor = (processor_t)dequeue_head(&pset->idle_queue);
- pset->idle_count--;
- processor->next_thread = new_thread;
- if (new_thread->sched_pri >= BASEPRI_RTQUEUES)
- processor->deadline = new_thread->realtime.deadline;
- else
- processor->deadline = UINT64_MAX;
- processor->state = PROCESSOR_DISPATCHING;
- dispatch_counts.idle_pset_any++;
- simple_unlock(&pset->sched_lock);
- if (processor != current_processor())
- machine_signal_idle(processor);
- return;
- }
-
- if (new_thread->sched_pri >= BASEPRI_RTQUEUES)
- realtime_schedule_insert(pset, new_thread);
- else {
- if (!run_queue_enqueue(&pset->runq, new_thread, options))
- preempt = AST_NONE;
+ if (thread->affinity_set != AFFINITY_SET_NULL) {
+ /*
+ * Use affinity set policy hint.
+ */
+ pset = thread->affinity_set->aset_pset;
+ pset_lock(pset);
+ processor = choose_processor(pset, thread);
+ }
+ else
+ if (thread->last_processor != PROCESSOR_NULL) {
/*
- * Update the timesharing quanta.
+ * Simple (last processor) affinity case.
*/
- timeshare_quanta_update(pset);
-
+ processor = thread->last_processor;
+ pset = processor->processor_set;
+ pset_lock(pset);
+
/*
- * Preempt check.
+ * Choose a different processor in certain cases.
*/
- if (preempt != AST_NONE) {
- /*
- * First try the current processor
- * if it is a member of the correct
- * processor set.
- */
- processor = current_processor();
- thread = processor->active_thread;
- if ( pset == processor->processor_set &&
- csw_needed(thread, processor) ) {
- dispatch_counts.pset_self++;
- simple_unlock(&pset->sched_lock);
-
- ast_on(preempt);
- return;
- }
-
+ if (thread->sched_pri >= BASEPRI_RTQUEUES) {
/*
- * If that failed and we have other
- * processors available keep trying.
+ * If the processor is executing an RT thread with
+ * an earlier deadline, choose another.
*/
- if ( pset->processor_count > 1 ||
- pset != processor->processor_set ) {
- queue_t queue = &pset->active_queue;
- processor_t myprocessor, lastprocessor;
- queue_entry_t next;
-
- /*
- * Next try the last processor
- * dispatched on.
- */
- myprocessor = processor;
- processor = new_thread->last_processor;
- if ( processor != myprocessor &&
- processor != PROCESSOR_NULL &&
- processor->processor_set == pset &&
- processor->state == PROCESSOR_RUNNING &&
- new_thread->sched_pri > processor->current_pri ) {
- dispatch_counts.pset_last++;
- cause_ast_check(processor);
- simple_unlock(&pset->sched_lock);
- return;
- }
+ if (thread->sched_pri <= processor->current_pri ||
+ thread->realtime.deadline >= processor->deadline)
+ processor = choose_processor(pset, thread);
+ }
+ else
+ processor = choose_processor(pset, thread);
+ }
+ else {
+ /*
+ * No Affinity case:
+ *
+ * Utilitize a per task hint to spread threads
+ * among the available processor sets.
+ */
+ task_t task = thread->task;
- /*
- * Lastly, pick any other
- * available processor.
- */
- lastprocessor = processor;
- processor = (processor_t)queue_first(queue);
- while (!queue_end(queue, (queue_entry_t)processor)) {
- next = queue_next((queue_entry_t)processor);
-
- if ( processor != myprocessor &&
- processor != lastprocessor &&
- new_thread->sched_pri >
- processor->current_pri ) {
- if (!queue_end(queue, next)) {
- remqueue(queue, (queue_entry_t)processor);
- enqueue_tail(queue, (queue_entry_t)processor);
- }
- dispatch_counts.pset_other++;
- cause_ast_check(processor);
- simple_unlock(&pset->sched_lock);
- return;
- }
+ pset = task->pset_hint;
+ if (pset == PROCESSOR_SET_NULL)
+ pset = current_processor()->processor_set;
- processor = (processor_t)next;
- }
- }
- }
+ pset = choose_next_pset(pset);
+ pset_lock(pset);
- simple_unlock(&pset->sched_lock);
+ processor = choose_processor(pset, thread);
+ task->pset_hint = processor->processor_set;
}
}
else {
- /*
- * Bound, can only run on bound processor. Have to lock
- * processor here because it may not be the current one.
- */
- processor_lock(processor);
+ /*
+ * Bound case:
+ *
+ * Unconditionally dispatch on the processor.
+ */
+ processor = thread->bound_processor;
pset = processor->processor_set;
- if (pset != PROCESSOR_SET_NULL) {
- simple_lock(&pset->sched_lock);
- if (processor->state == PROCESSOR_IDLE) {
- remqueue(&pset->idle_queue, (queue_entry_t)processor);
- pset->idle_count--;
- processor->next_thread = new_thread;
- processor->deadline = UINT64_MAX;
- processor->state = PROCESSOR_DISPATCHING;
- dispatch_counts.idle_bound++;
- simple_unlock(&pset->sched_lock);
- processor_unlock(processor);
- if (processor != current_processor())
- machine_signal_idle(processor);
- return;
- }
- }
-
- if (!run_queue_enqueue(&processor->runq, new_thread, options))
- preempt = AST_NONE;
-
- if (preempt != AST_NONE) {
- if (processor == current_processor()) {
- thread = processor->active_thread;
- if (csw_needed(thread, processor)) {
- dispatch_counts.bound_self++;
- ast_on(preempt);
+ pset_lock(pset);
+ }
+
+ /*
+ * Dispatch the thread on the choosen processor.
+ */
+ if (thread->sched_pri >= BASEPRI_RTQUEUES)
+ realtime_setrun(processor, thread);
+ else
+ processor_setrun(processor, thread, options);
+}
+
+/*
+ * processor_queue_shutdown:
+ *
+ * Shutdown a processor run queue by
+ * re-dispatching non-bound threads.
+ *
+ * Associated pset must be locked, and is
+ * returned unlocked.
+ */
+void
+processor_queue_shutdown(
+ processor_t processor)
+{
+ processor_set_t pset = processor->processor_set;
+ run_queue_t rq = &processor->runq;
+ queue_t queue = rq->queues + rq->highq;
+ int pri = rq->highq, count = rq->count;
+ thread_t next, thread;
+ queue_head_t tqueue;
+
+ queue_init(&tqueue);
+
+ while (count > 0) {
+ thread = (thread_t)queue_first(queue);
+ while (!queue_end(queue, (queue_entry_t)thread)) {
+ next = (thread_t)queue_next((queue_entry_t)thread);
+
+ if (thread->bound_processor != processor) {
+ remqueue(queue, (queue_entry_t)thread);
+
+ thread->runq = PROCESSOR_NULL;
+ rq->count--;
+ if (testbit(pri, sched_preempt_pri)) {
+ rq->urgency--; assert(rq->urgency >= 0);
}
+ if (queue_empty(queue)) {
+ if (pri != IDLEPRI)
+ clrbit(MAXPRI - pri, rq->bitmap);
+ rq->highq = MAXPRI - ffsbit(rq->bitmap);
+ }
+
+ enqueue_tail(&tqueue, (queue_entry_t)thread);
}
- else
- if ( processor->state == PROCESSOR_RUNNING &&
- new_thread->sched_pri > processor->current_pri ) {
- dispatch_counts.bound_other++;
- cause_ast_check(processor);
- }
+ count--;
+
+ thread = next;
}
- if (pset != PROCESSOR_SET_NULL)
- simple_unlock(&pset->sched_lock);
+ queue--; pri--;
+ }
+
+ pset_unlock(pset);
+
+ while ((thread = (thread_t)dequeue_head(&tqueue)) != THREAD_NULL) {
+ thread_lock(thread);
+
+ thread_setrun(thread, SCHED_TAILQ);
- processor_unlock(processor);
+ thread_unlock(thread);
}
}
/*
- * Check for a possible preemption point in
- * the (current) thread.
+ * Check for a preemption point in
+ * the current context.
*
* Called at splsched.
*/
ast_t
csw_check(
- thread_t thread,
processor_t processor)
{
- int current_pri = thread->sched_pri;
ast_t result = AST_NONE;
run_queue_t runq;
if (first_timeslice(processor)) {
- runq = &processor->processor_set->runq;
+ runq = &rt_runq;
if (runq->highq >= BASEPRI_RTQUEUES)
return (AST_PREEMPT | AST_URGENT);
- if (runq->highq > current_pri) {
+ if (runq->highq > processor->current_pri) {
if (runq->urgency > 0)
return (AST_PREEMPT | AST_URGENT);
}
runq = &processor->runq;
- if (runq->highq > current_pri) {
+ if (runq->highq > processor->current_pri) {
if (runq->urgency > 0)
return (AST_PREEMPT | AST_URGENT);
}
}
else {
- runq = &processor->processor_set->runq;
- if (runq->highq >= current_pri) {
+ runq = &rt_runq;
+ if (runq->highq >= processor->current_pri) {
if (runq->urgency > 0)
return (AST_PREEMPT | AST_URGENT);
}
runq = &processor->runq;
- if (runq->highq >= current_pri) {
+ if (runq->highq >= processor->current_pri) {
if (runq->urgency > 0)
return (AST_PREEMPT | AST_URGENT);
if (result != AST_NONE)
return (result);
- if (thread->state & TH_SUSP)
- result |= AST_PREEMPT;
+ if (machine_cpu_is_inactive(processor->cpu_num))
+ return (AST_PREEMPT);
- return (result);
+ if (processor->active_thread->state & TH_SUSP)
+ return (AST_PREEMPT);
+
+ return (AST_NONE);
}
/*
*/
void
set_sched_pri(
- thread_t thread,
- int priority)
+ thread_t thread,
+ int priority)
{
- register struct run_queue *rq = run_queue_remove(thread);
-
- if ( !(thread->sched_mode & TH_MODE_TIMESHARE) &&
- (priority >= BASEPRI_PREEMPT ||
- (thread->task_priority < MINPRI_KERNEL &&
- thread->task_priority >= BASEPRI_BACKGROUND &&
- priority > thread->task_priority) ||
- (thread->sched_mode & TH_MODE_FORCEDPREEMPT) ) )
- thread->sched_mode |= TH_MODE_PREEMPT;
- else
- thread->sched_mode &= ~TH_MODE_PREEMPT;
+ boolean_t removed = run_queue_remove(thread);
thread->sched_pri = priority;
- if (rq != RUN_QUEUE_NULL)
+ if (removed)
thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
else
if (thread->state & TH_RUN) {
processor_t processor = thread->last_processor;
if (thread == current_thread()) {
- ast_t preempt = csw_check(thread, processor);
+ ast_t preempt;
- if (preempt != AST_NONE)
- ast_on(preempt);
processor->current_pri = priority;
+ if ((preempt = csw_check(processor)) != AST_NONE)
+ ast_on(preempt);
}
else
if ( processor != PROCESSOR_NULL &&
}
}
+#if 0
+
+static void
+run_queue_check(
+ run_queue_t rq,
+ thread_t thread)
+{
+ queue_t q;
+ queue_entry_t qe;
+
+ if (rq != thread->runq)
+ panic("run_queue_check: thread runq");
+
+ if (thread->sched_pri > MAXPRI || thread->sched_pri < MINPRI)
+ panic("run_queue_check: thread sched_pri");
+
+ q = &rq->queues[thread->sched_pri];
+ qe = queue_first(q);
+ while (!queue_end(q, qe)) {
+ if (qe == (queue_entry_t)thread)
+ return;
+
+ qe = queue_next(qe);
+ }
+
+ panic("run_queue_check: end");
+}
+
+#endif /* DEBUG */
+
/*
* run_queue_remove:
*
- * Remove a thread from its current run queue and
- * return the run queue if successful.
+ * Remove a thread from a current run queue and
+ * return TRUE if successful.
*
* Thread must be locked.
*/
-run_queue_t
+boolean_t
run_queue_remove(
- thread_t thread)
+ thread_t thread)
{
- register run_queue_t rq = thread->runq;
+ processor_t processor = thread->runq;
/*
- * If rq is RUN_QUEUE_NULL, the thread will stay out of the
+ * If processor is PROCESSOR_NULL, the thread will stay out of the
* run queues because the caller locked the thread. Otherwise
* the thread is on a run queue, but could be chosen for dispatch
* and removed.
*/
- if (rq != RUN_QUEUE_NULL) {
- processor_set_t pset = thread->processor_set;
- processor_t processor = thread->bound_processor;
+ if (processor != PROCESSOR_NULL) {
+ void * rqlock;
+ run_queue_t rq;
/*
- * The run queues are locked by the pset scheduling
- * lock, except when a processor is off-line the
- * local run queue is locked by the processor lock.
+ * The processor run queues are locked by the
+ * processor set. Real-time priorities use a
+ * global queue with a dedicated lock.
*/
- if (processor != PROCESSOR_NULL) {
- processor_lock(processor);
- pset = processor->processor_set;
+ if (thread->sched_pri < BASEPRI_RTQUEUES) {
+ rqlock = &processor->processor_set->sched_lock;
+ rq = &processor->runq;
+ }
+ else {
+ rqlock = &rt_lock; rq = &rt_runq;
}
- if (pset != PROCESSOR_SET_NULL)
- simple_lock(&pset->sched_lock);
+ simple_lock(rqlock);
- if (rq == thread->runq) {
+ if (processor == thread->runq) {
/*
* Thread is on a run queue and we have a lock on
* that run queue.
*/
remqueue(&rq->queues[0], (queue_entry_t)thread);
rq->count--;
- if (thread->sched_mode & TH_MODE_PREEMPT)
- rq->urgency--;
- assert(rq->urgency >= 0);
+ if (testbit(thread->sched_pri, sched_preempt_pri)) {
+ rq->urgency--; assert(rq->urgency >= 0);
+ }
if (queue_empty(rq->queues + thread->sched_pri)) {
/* update run queue status */
rq->highq = MAXPRI - ffsbit(rq->bitmap);
}
- thread->runq = RUN_QUEUE_NULL;
+ thread->runq = PROCESSOR_NULL;
}
else {
/*
* The thread left the run queue before we could
* lock the run queue.
*/
- assert(thread->runq == RUN_QUEUE_NULL);
- rq = RUN_QUEUE_NULL;
+ assert(thread->runq == PROCESSOR_NULL);
+ processor = PROCESSOR_NULL;
}
- if (pset != PROCESSOR_SET_NULL)
- simple_unlock(&pset->sched_lock);
-
- if (processor != PROCESSOR_NULL)
- processor_unlock(processor);
+ simple_unlock(rqlock);
}
- return (rq);
+ return (processor != PROCESSOR_NULL);
}
/*
- * choose_thread:
+ * steal_processor_thread:
*
- * Remove a thread to execute from the run queues
- * and return it.
+ * Locate a thread to steal from the processor and
+ * return it.
*
- * Called with pset scheduling lock held.
+ * Associated pset must be locked. Returns THREAD_NULL
+ * on failure.
*/
static thread_t
-choose_thread(
- processor_set_t pset,
- processor_t processor)
+steal_processor_thread(
+ processor_t processor)
{
- register run_queue_t runq;
- register thread_t thread;
- register queue_t q;
+ run_queue_t rq = &processor->runq;
+ queue_t queue = rq->queues + rq->highq;
+ int pri = rq->highq, count = rq->count;
+ thread_t thread;
+
+ while (count > 0) {
+ thread = (thread_t)queue_first(queue);
+ while (!queue_end(queue, (queue_entry_t)thread)) {
+ if (thread->bound_processor != processor) {
+ remqueue(queue, (queue_entry_t)thread);
+
+ thread->runq = PROCESSOR_NULL;
+ rq->count--;
+ if (testbit(pri, sched_preempt_pri)) {
+ rq->urgency--; assert(rq->urgency >= 0);
+ }
+ if (queue_empty(queue)) {
+ if (pri != IDLEPRI)
+ clrbit(MAXPRI - pri, rq->bitmap);
+ rq->highq = MAXPRI - ffsbit(rq->bitmap);
+ }
- runq = &processor->runq;
-
- if (runq->count > 0 && runq->highq >= pset->runq.highq) {
- q = runq->queues + runq->highq;
-
- thread = (thread_t)q->next;
- ((queue_entry_t)thread)->next->prev = q;
- q->next = ((queue_entry_t)thread)->next;
- thread->runq = RUN_QUEUE_NULL;
- runq->count--;
- if (thread->sched_mode & TH_MODE_PREEMPT)
- runq->urgency--;
- assert(runq->urgency >= 0);
- if (queue_empty(q)) {
- if (runq->highq != IDLEPRI)
- clrbit(MAXPRI - runq->highq, runq->bitmap);
- runq->highq = MAXPRI - ffsbit(runq->bitmap);
- }
+ return (thread);
+ }
+ count--;
- processor->deadline = UINT64_MAX;
+ thread = (thread_t)queue_next((queue_entry_t)thread);
+ }
- return (thread);
+ queue--; pri--;
}
- runq = &pset->runq;
+ return (THREAD_NULL);
+}
+
+/*
+ * Locate and steal a thread, beginning
+ * at the pset.
+ *
+ * The pset must be locked, and is returned
+ * unlocked.
+ *
+ * Returns the stolen thread, or THREAD_NULL on
+ * failure.
+ */
+static thread_t
+steal_thread(
+ processor_set_t pset)
+{
+ processor_set_t nset, cset = pset;
+ processor_t processor;
+ thread_t thread;
+
+ do {
+ processor = (processor_t)queue_first(&cset->active_queue);
+ while (!queue_end(&cset->active_queue, (queue_entry_t)processor)) {
+ if (processor->runq.count > 0) {
+ thread = steal_processor_thread(processor);
+ if (thread != THREAD_NULL) {
+ remqueue(&cset->active_queue, (queue_entry_t)processor);
+ enqueue_tail(&cset->active_queue, (queue_entry_t)processor);
- assert(runq->count > 0);
- q = runq->queues + runq->highq;
+ pset_unlock(cset);
- thread = (thread_t)q->next;
- ((queue_entry_t)thread)->next->prev = q;
- q->next = ((queue_entry_t)thread)->next;
- thread->runq = RUN_QUEUE_NULL;
- runq->count--;
- if (runq->highq >= BASEPRI_RTQUEUES)
- processor->deadline = thread->realtime.deadline;
- else
- processor->deadline = UINT64_MAX;
- if (thread->sched_mode & TH_MODE_PREEMPT)
- runq->urgency--;
- assert(runq->urgency >= 0);
- if (queue_empty(q)) {
- if (runq->highq != IDLEPRI)
- clrbit(MAXPRI - runq->highq, runq->bitmap);
- runq->highq = MAXPRI - ffsbit(runq->bitmap);
- }
+ return (thread);
+ }
+ }
- timeshare_quanta_update(pset);
+ processor = (processor_t)queue_next((queue_entry_t)processor);
+ }
- return (thread);
-}
+ nset = next_pset(cset);
-/*
- * no_dispatch_count counts number of times processors go non-idle
- * without being dispatched. This should be very rare.
- */
-int no_dispatch_count = 0;
+ if (nset != pset) {
+ pset_unlock(cset);
+
+ cset = nset;
+ pset_lock(cset);
+ }
+ } while (nset != pset);
+
+ pset_unlock(cset);
+
+ return (THREAD_NULL);
+}
/*
- * This is the idle thread, which just looks for other threads
- * to execute.
+ * This is the processor idle loop, which just looks for other threads
+ * to execute. Processor idle threads invoke this without supplying a
+ * current thread to idle without an asserted wait state.
+ *
+ * Returns a the next thread to execute if dispatched directly.
*/
-void
-idle_thread_continue(void)
+static thread_t
+processor_idle(
+ thread_t thread,
+ processor_t processor)
{
- register processor_t processor;
- register volatile thread_t *threadp;
- register volatile int *gcount;
- register volatile int *lcount;
- register thread_t new_thread;
- register int state;
- register processor_set_t pset;
- int mycpu;
+ processor_set_t pset = processor->processor_set;
+ thread_t new_thread;
+ int state;
- mycpu = cpu_number();
- processor = cpu_to_processor(mycpu);
- threadp = (volatile thread_t *) &processor->next_thread;
- lcount = (volatile int *) &processor->runq.count;
+ (void)splsched();
- gcount = (volatile int *)&processor->processor_set->runq.count;
+#ifdef __ppc__
+ pmsDown(); /* Step power down */
+#endif
- (void)splsched();
- while ( (*threadp == (volatile thread_t)THREAD_NULL) &&
- (*gcount == 0) && (*lcount == 0) ) {
-
- /* check for ASTs while we wait */
- if (need_ast[mycpu] &~ ( AST_SCHEDULING | AST_BSD )) {
- /* no ASTs for us */
- need_ast[mycpu] &= AST_NONE;
- (void)spllo();
- }
- else
- machine_idle();
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED,MACH_IDLE) | DBG_FUNC_START, (int)thread, 0, 0, 0, 0);
+
+ timer_switch(&PROCESSOR_DATA(processor, system_state),
+ mach_absolute_time(), &PROCESSOR_DATA(processor, idle_state));
+ PROCESSOR_DATA(processor, current_state) = &PROCESSOR_DATA(processor, idle_state);
+
+ while (processor->next_thread == THREAD_NULL && processor->runq.count == 0 && rt_runq.count == 0 &&
+ (thread == THREAD_NULL || ((thread->state & (TH_WAIT|TH_SUSP)) == TH_WAIT && !thread->wake_active))) {
+ machine_idle();
(void)splsched();
+
+ if (processor->state == PROCESSOR_INACTIVE && !machine_cpu_is_inactive(processor->cpu_num))
+ break;
}
- /*
- * This is not a switch statement to avoid the
- * bounds checking code in the common case.
- */
- pset = processor->processor_set;
- simple_lock(&pset->sched_lock);
+ timer_switch(&PROCESSOR_DATA(processor, idle_state),
+ mach_absolute_time(), &PROCESSOR_DATA(processor, system_state));
+ PROCESSOR_DATA(processor, current_state) = &PROCESSOR_DATA(processor, system_state);
+
+ pset_lock(pset);
+
+#ifdef __ppc__
+ pmsStep(0); /* Step up out of idle power */
+#endif
state = processor->state;
if (state == PROCESSOR_DISPATCHING) {
/*
* Commmon case -- cpu dispatched.
*/
- new_thread = *threadp;
- *threadp = (volatile thread_t) THREAD_NULL;
+ new_thread = processor->next_thread;
+ processor->next_thread = THREAD_NULL;
processor->state = PROCESSOR_RUNNING;
- enqueue_tail(&pset->active_queue, (queue_entry_t)processor);
- if ( pset->runq.highq >= BASEPRI_RTQUEUES &&
- new_thread->sched_pri >= BASEPRI_RTQUEUES ) {
- register run_queue_t runq = &pset->runq;
- register queue_t q;
-
- q = runq->queues + runq->highq;
- if (((thread_t)q->next)->realtime.deadline <
- processor->deadline) {
- thread_t thread = new_thread;
-
- new_thread = (thread_t)q->next;
- ((queue_entry_t)new_thread)->next->prev = q;
- q->next = ((queue_entry_t)new_thread)->next;
- new_thread->runq = RUN_QUEUE_NULL;
- processor->deadline = new_thread->realtime.deadline;
- assert(new_thread->sched_mode & TH_MODE_PREEMPT);
- runq->count--; runq->urgency--;
- if (queue_empty(q)) {
- if (runq->highq != IDLEPRI)
- clrbit(MAXPRI - runq->highq, runq->bitmap);
- runq->highq = MAXPRI - ffsbit(runq->bitmap);
- }
- dispatch_counts.missed_realtime++;
- simple_unlock(&pset->sched_lock);
+ if ( processor->runq.highq > new_thread->sched_pri ||
+ (rt_runq.highq > 0 && rt_runq.highq >= new_thread->sched_pri) ) {
+ processor->deadline = UINT64_MAX;
- thread_lock(thread);
- thread_setrun(thread, SCHED_HEADQ);
- thread_unlock(thread);
+ pset_unlock(pset);
- counter(c_idle_thread_handoff++);
- thread_run(processor->idle_thread,
- idle_thread_continue, new_thread);
- /*NOTREACHED*/
- }
- simple_unlock(&pset->sched_lock);
+ thread_lock(new_thread);
+ thread_setrun(new_thread, SCHED_HEADQ);
+ thread_unlock(new_thread);
- counter(c_idle_thread_handoff++);
- thread_run(processor->idle_thread,
- idle_thread_continue, new_thread);
- /*NOTREACHED*/
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED,MACH_IDLE) | DBG_FUNC_END, (int)thread, (int)state, 0, 0, 0);
+
+ return (THREAD_NULL);
}
- if ( processor->runq.highq > new_thread->sched_pri ||
- pset->runq.highq > new_thread->sched_pri ) {
- thread_t thread = new_thread;
-
- new_thread = choose_thread(pset, processor);
- dispatch_counts.missed_other++;
- simple_unlock(&pset->sched_lock);
-
- thread_lock(thread);
- thread_setrun(thread, SCHED_HEADQ);
- thread_unlock(thread);
+ pset_unlock(pset);
- counter(c_idle_thread_handoff++);
- thread_run(processor->idle_thread,
- idle_thread_continue, new_thread);
- /* NOTREACHED */
- }
- else {
- simple_unlock(&pset->sched_lock);
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED,MACH_IDLE) | DBG_FUNC_END, (int)thread, (int)state, (int)new_thread, 0, 0);
- counter(c_idle_thread_handoff++);
- thread_run(processor->idle_thread,
- idle_thread_continue, new_thread);
- /* NOTREACHED */
- }
+ return (new_thread);
}
else
if (state == PROCESSOR_IDLE) {
- /*
- * Processor was not dispatched (Rare).
- * Set it running again and force a
- * reschedule.
- */
- no_dispatch_count++;
- pset->idle_count--;
remqueue(&pset->idle_queue, (queue_entry_t)processor);
+
+ processor->state = PROCESSOR_RUNNING;
+ enqueue_tail(&pset->active_queue, (queue_entry_t)processor);
+ }
+ else
+ if (state == PROCESSOR_INACTIVE) {
processor->state = PROCESSOR_RUNNING;
enqueue_tail(&pset->active_queue, (queue_entry_t)processor);
- simple_unlock(&pset->sched_lock);
-
- counter(c_idle_thread_block++);
- thread_block(idle_thread_continue);
- /* NOTREACHED */
}
else
if (state == PROCESSOR_SHUTDOWN) {
* Going off-line. Force a
* reschedule.
*/
- if ((new_thread = (thread_t)*threadp) != THREAD_NULL) {
- *threadp = (volatile thread_t) THREAD_NULL;
+ if ((new_thread = processor->next_thread) != THREAD_NULL) {
+ processor->next_thread = THREAD_NULL;
processor->deadline = UINT64_MAX;
- simple_unlock(&pset->sched_lock);
+
+ pset_unlock(pset);
thread_lock(new_thread);
thread_setrun(new_thread, SCHED_HEADQ);
thread_unlock(new_thread);
- }
- else
- simple_unlock(&pset->sched_lock);
- counter(c_idle_thread_block++);
- thread_block(idle_thread_continue);
- /* NOTREACHED */
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED,MACH_IDLE) | DBG_FUNC_END, (int)thread, (int)state, 0, 0, 0);
+
+ return (THREAD_NULL);
+ }
}
- simple_unlock(&pset->sched_lock);
+ pset_unlock(pset);
- panic("idle_thread: state %d\n", cpu_state(mycpu));
- /*NOTREACHED*/
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED,MACH_IDLE) | DBG_FUNC_END, (int)thread, (int)state, 0, 0, 0);
+
+ return (THREAD_NULL);
}
+/*
+ * Each processor has a dedicated thread which
+ * executes the idle loop when there is no suitable
+ * previous context.
+ */
void
idle_thread(void)
{
- counter(c_idle_thread_block++);
- thread_block(idle_thread_continue);
+ processor_t processor = current_processor();
+ thread_t new_thread;
+
+ new_thread = processor_idle(THREAD_NULL, processor);
+ if (new_thread != THREAD_NULL) {
+ thread_run(processor->idle_thread, (thread_continue_t)idle_thread, NULL, new_thread);
+ /*NOTREACHED*/
+ }
+
+ thread_block((thread_continue_t)idle_thread);
/*NOTREACHED*/
}
-static uint64_t sched_tick_deadline;
+kern_return_t
+idle_thread_create(
+ processor_t processor)
+{
+ kern_return_t result;
+ thread_t thread;
+ spl_t s;
+
+ result = kernel_thread_create((thread_continue_t)idle_thread, NULL, MAXPRI_KERNEL, &thread);
+ if (result != KERN_SUCCESS)
+ return (result);
-void sched_tick_thread(void);
+ s = splsched();
+ thread_lock(thread);
+ thread->bound_processor = processor;
+ processor->idle_thread = thread;
+ thread->sched_pri = thread->priority = IDLEPRI;
+ thread->state = (TH_RUN | TH_IDLE);
+ thread_unlock(thread);
+ splx(s);
-void
-sched_tick_init(void)
-{
- kernel_thread_with_priority(sched_tick_thread, MAXPRI_STANDARD);
+ thread_deallocate(thread);
+
+ return (KERN_SUCCESS);
}
+static uint64_t sched_tick_deadline;
+
/*
- * sched_tick_thread
+ * sched_startup:
*
- * Perform periodic bookkeeping functions about ten
- * times per second.
+ * Kicks off scheduler services.
+ *
+ * Called at splsched.
*/
void
-sched_tick_thread_continue(void)
+sched_startup(void)
{
- uint64_t abstime;
-#if SIMPLE_CLOCK
- int new_usec;
-#endif /* SIMPLE_CLOCK */
+ kern_return_t result;
+ thread_t thread;
+
+ result = kernel_thread_start_priority((thread_continue_t)sched_tick_thread, NULL, MAXPRI_KERNEL, &thread);
+ if (result != KERN_SUCCESS)
+ panic("sched_startup");
- abstime = mach_absolute_time();
+ thread_deallocate(thread);
- sched_tick++; /* age usage one more time */
-#if SIMPLE_CLOCK
/*
- * Compensate for clock drift. sched_usec is an
- * exponential average of the number of microseconds in
- * a second. It decays in the same fashion as cpu_usage.
+ * Yield to the sched_tick_thread while it times
+ * a series of context switches back. It stores
+ * the baseline value in sched_cswtime.
+ *
+ * The current thread is the only other thread
+ * active at this point.
*/
- new_usec = sched_usec_elapsed();
- sched_usec = (5*sched_usec + 3*new_usec)/8;
-#endif /* SIMPLE_CLOCK */
+ while (sched_cswtime == 0)
+ thread_block(THREAD_CONTINUE_NULL);
+
+ thread_daemon_init();
+
+ thread_call_initialize();
+}
+
+/*
+ * sched_tick_thread:
+ *
+ * Perform periodic bookkeeping functions about ten
+ * times per second.
+ */
+static void
+sched_tick_continue(void)
+{
+ uint64_t abstime = mach_absolute_time();
+
+ sched_tick++;
/*
- * Compute the scheduler load factors.
+ * Compute various averages.
*/
- compute_mach_factor();
+ compute_averages();
/*
- * Scan the run queues for timesharing threads which
- * may need to have their priorities recalculated.
+ * Scan the run queues for threads which
+ * may need to be updated.
*/
- do_thread_scan();
+ thread_update_scan();
clock_deadline_for_periodic_event(sched_tick_interval, abstime,
&sched_tick_deadline);
- assert_wait((event_t)sched_tick_thread_continue, THREAD_INTERRUPTIBLE);
- thread_set_timer_deadline(sched_tick_deadline);
- thread_block(sched_tick_thread_continue);
+ assert_wait_deadline((event_t)sched_tick_thread, THREAD_UNINT, sched_tick_deadline);
+ thread_block((thread_continue_t)sched_tick_continue);
/*NOTREACHED*/
}
+/*
+ * Time a series of context switches to determine
+ * a baseline. Toss the high and low and return
+ * the one-way value.
+ */
+static uint32_t
+time_cswitch(void)
+{
+ uint32_t new, hi, low, accum;
+ uint64_t abstime;
+ int i, tries = 7;
+
+ accum = hi = low = 0;
+ for (i = 0; i < tries; ++i) {
+ abstime = mach_absolute_time();
+ thread_block(THREAD_CONTINUE_NULL);
+
+ new = mach_absolute_time() - abstime;
+
+ if (i == 0)
+ accum = hi = low = new;
+ else {
+ if (new < low)
+ low = new;
+ else
+ if (new > hi)
+ hi = new;
+ accum += new;
+ }
+ }
+
+ return ((accum - hi - low) / (2 * (tries - 2)));
+}
+
void
sched_tick_thread(void)
{
+ sched_cswtime = time_cswitch();
+
sched_tick_deadline = mach_absolute_time();
- thread_block(sched_tick_thread_continue);
+ sched_tick_continue();
/*NOTREACHED*/
}
/*
- * do_thread_scan:
+ * thread_update_scan / runq_scan:
*
- * Scan the run queues for timesharing threads which need
- * to be aged, possibily adjusting their priorities upwards.
+ * Scan the run queues to account for timesharing threads
+ * which need to be updated.
*
* Scanner runs in two passes. Pass one squirrels likely
- * thread away in an array (takes out references for them).
- * Pass two does the priority updates. This is necessary because
- * the run queue lock is required for the candidate scan, but
- * cannot be held during updates.
+ * threads away in an array, pass two does the update.
*
- * Array length should be enough so that restart isn't necessary,
- * but restart logic is included.
+ * This is necessary because the run queue is locked for
+ * the candidate scan, but the thread is locked for the update.
*
+ * Array should be sized to make forward progress, without
+ * disabling preemption for long periods.
*/
-#define MAX_STUCK_THREADS 128
+#define THREAD_UPDATE_SIZE 128
-static thread_t stuck_threads[MAX_STUCK_THREADS];
-static int stuck_count = 0;
+static thread_t thread_update_array[THREAD_UPDATE_SIZE];
+static int thread_update_count = 0;
/*
- * do_runq_scan is the guts of pass 1. It scans a runq for
- * stuck threads. A boolean is returned indicating whether
- * a retry is needed.
+ * Scan a runq for candidate threads.
+ *
+ * Returns TRUE if retry is needed.
*/
static boolean_t
-do_runq_scan(
+runq_scan(
run_queue_t runq)
{
+ register int count;
register queue_t q;
register thread_t thread;
- register int count;
- boolean_t result = FALSE;
if ((count = runq->count) > 0) {
q = runq->queues + runq->highq;
queue_iterate(q, thread, thread_t, links) {
if ( thread->sched_stamp != sched_tick &&
(thread->sched_mode & TH_MODE_TIMESHARE) ) {
- /*
- * Stuck, save its id for later.
- */
- if (stuck_count == MAX_STUCK_THREADS) {
- /*
- * !@#$% No more room.
- */
+ if (thread_update_count == THREAD_UPDATE_SIZE)
return (TRUE);
- }
- if (thread_lock_try(thread)) {
- thread->ref_count++;
- thread_unlock(thread);
- stuck_threads[stuck_count++] = thread;
- }
- else
- result = TRUE;
+ thread_update_array[thread_update_count++] = thread;
+ thread_reference_internal(thread);
}
count--;
}
}
- return (result);
+ return (FALSE);
}
-boolean_t thread_scan_enabled = TRUE;
-
static void
-do_thread_scan(void)
+thread_update_scan(void)
{
- register boolean_t restart_needed = FALSE;
- register thread_t thread;
- register processor_set_t pset = &default_pset;
- register processor_t processor;
- spl_t s;
-
- if (!thread_scan_enabled)
- return;
+ boolean_t restart_needed = FALSE;
+ processor_t processor = processor_list;
+ processor_set_t pset;
+ thread_t thread;
+ spl_t s;
do {
- s = splsched();
- simple_lock(&pset->sched_lock);
- restart_needed = do_runq_scan(&pset->runq);
- simple_unlock(&pset->sched_lock);
-
- if (!restart_needed) {
- simple_lock(&pset->sched_lock);
- processor = (processor_t)queue_first(&pset->processors);
- while (!queue_end(&pset->processors, (queue_entry_t)processor)) {
- if (restart_needed = do_runq_scan(&processor->runq))
- break;
+ do {
+ pset = processor->processor_set;
- thread = processor->idle_thread;
- if (thread->sched_stamp != sched_tick) {
- if (stuck_count == MAX_STUCK_THREADS) {
- restart_needed = TRUE;
- break;
- }
+ s = splsched();
+ pset_lock(pset);
+
+ restart_needed = runq_scan(&processor->runq);
+
+ pset_unlock(pset);
+ splx(s);
+
+ if (restart_needed)
+ break;
- stuck_threads[stuck_count++] = thread;
+ thread = processor->idle_thread;
+ if (thread != THREAD_NULL && thread->sched_stamp != sched_tick) {
+ if (thread_update_count == THREAD_UPDATE_SIZE) {
+ restart_needed = TRUE;
+ break;
}
- processor = (processor_t)queue_next(&processor->processors);
+ thread_update_array[thread_update_count++] = thread;
+ thread_reference_internal(thread);
}
- simple_unlock(&pset->sched_lock);
- }
- splx(s);
+ } while ((processor = processor->processor_list) != NULL);
/*
* Ok, we now have a collection of candidates -- fix them.
*/
- while (stuck_count > 0) {
- boolean_t idle_thread;
-
- thread = stuck_threads[--stuck_count];
- stuck_threads[stuck_count] = THREAD_NULL;
+ while (thread_update_count > 0) {
+ thread = thread_update_array[--thread_update_count];
+ thread_update_array[thread_update_count] = THREAD_NULL;
s = splsched();
thread_lock(thread);
- idle_thread = (thread->state & TH_IDLE) != 0;
if ( !(thread->state & (TH_WAIT|TH_SUSP)) &&
thread->sched_stamp != sched_tick )
update_priority(thread);
thread_unlock(thread);
splx(s);
- if (!idle_thread)
- thread_deallocate(thread);
+ thread_deallocate(thread);
}
-
- if (restart_needed)
- delay(1); /* XXX */
-
} while (restart_needed);
}
thread_wakeup_with_result(x, THREAD_AWAKENED);
}
+boolean_t
+preemption_enabled(void)
+{
+ return (get_preemption_level() == 0 && ml_get_interrupts_enabled());
+}
#if DEBUG
static boolean_t
#if MACH_KDB
#include <ddb/db_output.h>
#define printf kdbprintf
-extern int db_indent;
void db_sched(void);
void
#if MACH_COUNTERS
iprintf("Thread block: calls %d\n",
c_thread_block_calls);
- iprintf("Idle thread:\n\thandoff %d block %d no_dispatch %d\n",
+ iprintf("Idle thread:\n\thandoff %d block %d\n",
c_idle_thread_handoff,
- c_idle_thread_block, no_dispatch_count);
+ c_idle_thread_block);
iprintf("Sched thread blocks: %d\n", c_sched_thread_block);
#endif /* MACH_COUNTERS */
db_indent -= 2;
projects / apple / xnu.git / blobdiff