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Commit e26b33e9 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge branch 'sched/clock' into sched/urgent

parents 279ef6bb cf206bff

include/linux/sched.h

+4 −27
Original line number Diff line number Diff line
@@ -1551,16 +1551,10 @@ static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) 


extern unsigned long long sched_clock(void);



#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK

static inline void sched_clock_init(void)

{

}



static inline u64 sched_clock_cpu(int cpu)

{

	return sched_clock();

}

extern void sched_clock_init(void);

extern u64 sched_clock_cpu(int cpu);



#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK

static inline void sched_clock_tick(void)

{

}
@@ -1572,28 +1566,11 @@ static inline void sched_clock_idle_sleep_event(void) 
static inline void sched_clock_idle_wakeup_event(u64 delta_ns)

{

}



#ifdef CONFIG_NO_HZ

static inline void sched_clock_tick_stop(int cpu)

{

}



static inline void sched_clock_tick_start(int cpu)

{

}

#endif



#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */

extern void sched_clock_init(void);

extern u64 sched_clock_cpu(int cpu);

#else

extern void sched_clock_tick(void);

extern void sched_clock_idle_sleep_event(void);

extern void sched_clock_idle_wakeup_event(u64 delta_ns);

#ifdef CONFIG_NO_HZ

extern void sched_clock_tick_stop(int cpu);

extern void sched_clock_tick_start(int cpu);

#endif

#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */



/*

 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu

kernel/sched_clock.c

+49 −114
Original line number Diff line number Diff line
@@ -42,12 +42,9 @@ unsigned long long __attribute__((weak)) sched_clock(void) 
	return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);

}



#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK

static __read_mostly int sched_clock_running;



#define MULTI_SHIFT 15

/* Max is double, Min is 1/2 */

#define MAX_MULTI (2LL << MULTI_SHIFT)

#define MIN_MULTI (1LL << (MULTI_SHIFT-1))

#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK



struct sched_clock_data {

	/*
@@ -58,14 +55,9 @@ struct sched_clock_data { 
	raw_spinlock_t		lock;



	unsigned long		tick_jiffies;

	u64			prev_raw;

	u64			tick_raw;

	u64			tick_gtod;

	u64			clock;

	s64			multi;

#ifdef CONFIG_NO_HZ

	int			check_max;

#endif

};



static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
@@ -80,8 +72,6 @@ static inline struct sched_clock_data *cpu_sdc(int cpu) 
	return &per_cpu(sched_clock_data, cpu);

}



static __read_mostly int sched_clock_running;



void sched_clock_init(void)

{

	u64 ktime_now = ktime_to_ns(ktime_get());
@@ -93,90 +83,39 @@ void sched_clock_init(void) 


		scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;

		scd->tick_jiffies = now_jiffies;

		scd->prev_raw = 0;

		scd->tick_raw = 0;

		scd->tick_gtod = ktime_now;

		scd->clock = ktime_now;

		scd->multi = 1 << MULTI_SHIFT;

#ifdef CONFIG_NO_HZ

		scd->check_max = 1;

#endif

	}



	sched_clock_running = 1;

}



#ifdef CONFIG_NO_HZ

/*

 * The dynamic ticks makes the delta jiffies inaccurate. This

 * prevents us from checking the maximum time update.

 * Disable the maximum check during stopped ticks.

 */

void sched_clock_tick_stop(int cpu)

{

	struct sched_clock_data *scd = cpu_sdc(cpu);



	scd->check_max = 0;

}



void sched_clock_tick_start(int cpu)

{

	struct sched_clock_data *scd = cpu_sdc(cpu);



	scd->check_max = 1;

}



static int check_max(struct sched_clock_data *scd)

{

	return scd->check_max;

}

#else

static int check_max(struct sched_clock_data *scd)

{

	return 1;

}

#endif /* CONFIG_NO_HZ */



/*

 * update the percpu scd from the raw @now value

 *

 *  - filter out backward motion

 *  - use jiffies to generate a min,max window to clip the raw values

 */

static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *time)

static u64 __update_sched_clock(struct sched_clock_data *scd, u64 now)

{

	unsigned long now_jiffies = jiffies;

	long delta_jiffies = now_jiffies - scd->tick_jiffies;

	u64 clock = scd->clock;

	u64 min_clock, max_clock;

	s64 delta = now - scd->prev_raw;

	s64 delta = now - scd->tick_raw;



	WARN_ON_ONCE(!irqs_disabled());



	/*

	 * At schedule tick the clock can be just under the gtod. We don't

	 * want to push it too prematurely.

	 */

	min_clock = scd->tick_gtod + (delta_jiffies * TICK_NSEC);

	if (min_clock > TICK_NSEC)

		min_clock -= TICK_NSEC / 2;

	min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC;



	if (unlikely(delta < 0)) {

		clock++;

		goto out;

	}



	/*

	 * The clock must stay within a jiffie of the gtod.

	 * But since we may be at the start of a jiffy or the end of one

	 * we add another jiffy buffer.

	 */

	max_clock = scd->tick_gtod + (2 + delta_jiffies) * TICK_NSEC;



	delta *= scd->multi;

	delta >>= MULTI_SHIFT;

	max_clock = min_clock + TICK_NSEC;



	if (unlikely(clock + delta > max_clock) && check_max(scd)) {

	if (unlikely(clock + delta > max_clock)) {

		if (clock < max_clock)

			clock = max_clock;

		else
@@ -189,12 +128,10 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim 
	if (unlikely(clock < min_clock))

		clock = min_clock;



	if (time)

		*time = clock;

	else {

		scd->prev_raw = now;

	scd->tick_jiffies = now_jiffies;

	scd->clock = clock;

	}



	return clock;

}



static void lock_double_clock(struct sched_clock_data *data1,
@@ -212,7 +149,7 @@ static void lock_double_clock(struct sched_clock_data *data1, 
u64 sched_clock_cpu(int cpu)

{

	struct sched_clock_data *scd = cpu_sdc(cpu);

	u64 now, clock;

	u64 now, clock, this_clock, remote_clock;



	if (unlikely(!sched_clock_running))

		return 0ull;
@@ -221,43 +158,44 @@ u64 sched_clock_cpu(int cpu) 
	now = sched_clock();



	if (cpu != raw_smp_processor_id()) {

		/*

		 * in order to update a remote cpu's clock based on our

		 * unstable raw time rebase it against:

		 *   tick_raw		(offset between raw counters)

		 *   tick_gotd          (tick offset between cpus)

		 */

		struct sched_clock_data *my_scd = this_scd();



		lock_double_clock(scd, my_scd);



		now -= my_scd->tick_raw;

		now += scd->tick_raw;

		this_clock = __update_sched_clock(my_scd, now);

		remote_clock = scd->clock;



		now += my_scd->tick_gtod;

		now -= scd->tick_gtod;

		/*

		 * Use the opportunity that we have both locks

		 * taken to couple the two clocks: we take the

		 * larger time as the latest time for both

		 * runqueues. (this creates monotonic movement)

		 */

		if (likely(remote_clock < this_clock)) {

			clock = this_clock;

			scd->clock = clock;

		} else {

			/*

			 * Should be rare, but possible:

			 */

			clock = remote_clock;

			my_scd->clock = remote_clock;

		}



		__raw_spin_unlock(&my_scd->lock);



		__update_sched_clock(scd, now, &clock);



		__raw_spin_unlock(&scd->lock);



	} else {

		__raw_spin_lock(&scd->lock);

		__update_sched_clock(scd, now, NULL);

		clock = scd->clock;

		__raw_spin_unlock(&scd->lock);

		clock = __update_sched_clock(scd, now);

	}



	__raw_spin_unlock(&scd->lock);



	return clock;

}



void sched_clock_tick(void)

{

	struct sched_clock_data *scd = this_scd();

	unsigned long now_jiffies = jiffies;

	s64 mult, delta_gtod, delta_raw;

	u64 now, now_gtod;



	if (unlikely(!sched_clock_running))
@@ -269,29 +207,14 @@ void sched_clock_tick(void) 
	now = sched_clock();



	__raw_spin_lock(&scd->lock);

	__update_sched_clock(scd, now, NULL);

	__update_sched_clock(scd, now);

	/*

	 * update tick_gtod after __update_sched_clock() because that will

	 * already observe 1 new jiffy; adding a new tick_gtod to that would

	 * increase the clock 2 jiffies.

	 */

	delta_gtod = now_gtod - scd->tick_gtod;

	delta_raw = now - scd->tick_raw;



	if ((long)delta_raw > 0) {

		mult = delta_gtod << MULTI_SHIFT;

		do_div(mult, delta_raw);

		scd->multi = mult;

		if (scd->multi > MAX_MULTI)

			scd->multi = MAX_MULTI;

		else if (scd->multi < MIN_MULTI)

			scd->multi = MIN_MULTI;

	} else

		scd->multi = 1 << MULTI_SHIFT;



	scd->tick_raw = now;

	scd->tick_gtod = now_gtod;

	scd->tick_jiffies = now_jiffies;

	__raw_spin_unlock(&scd->lock);

}
@@ -310,7 +233,6 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); 
void sched_clock_idle_wakeup_event(u64 delta_ns)

{

	struct sched_clock_data *scd = this_scd();

	u64 now = sched_clock();



	/*

	 * Override the previous timestamp and ignore all
@@ -319,15 +241,28 @@ void sched_clock_idle_wakeup_event(u64 delta_ns) 
	 * rq clock:

	 */

	__raw_spin_lock(&scd->lock);

	scd->prev_raw = now;

	scd->clock += delta_ns;

	scd->multi = 1 << MULTI_SHIFT;

	__raw_spin_unlock(&scd->lock);



	touch_softlockup_watchdog();

}

EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);



#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */



void sched_clock_init(void)

{

	sched_clock_running = 1;

}



u64 sched_clock_cpu(int cpu)

{

	if (unlikely(!sched_clock_running))

		return 0;



	return sched_clock();

}



#endif



unsigned long long cpu_clock(int cpu)

kernel/time/tick-sched.c

+0 −2
Original line number Diff line number Diff line
@@ -289,7 +289,6 @@ void tick_nohz_stop_sched_tick(int inidle) 
			ts->tick_stopped = 1;

			ts->idle_jiffies = last_jiffies;

			rcu_enter_nohz();

			sched_clock_tick_stop(cpu);

		}



		/*
@@ -392,7 +391,6 @@ void tick_nohz_restart_sched_tick(void) 
	select_nohz_load_balancer(0);

	now = ktime_get();

	tick_do_update_jiffies64(now);

	sched_clock_tick_start(cpu);

	cpu_clear(cpu, nohz_cpu_mask);



	/*