[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / sched / clock.c

/*
 * sched_clock for unstable cpu clocks
 *
 *  Copyright (C) 2008 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
 *
 *  Updates and enhancements:
 *    Copyright (C) 2008 Red Hat, Inc. Steven Rostedt <srostedt@redhat.com>
 *
 * Based on code by:
 *   Ingo Molnar <mingo@redhat.com>
 *   Guillaume Chazarain <guichaz@gmail.com>
 *
 *
 * What:
 *
 * cpu_clock(i) provides a fast (execution time) high resolution
 * clock with bounded drift between CPUs. The value of cpu_clock(i)
 * is monotonic for constant i. The timestamp returned is in nanoseconds.
 *
 * ######################### BIG FAT WARNING ##########################
 * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
 * # go backwards !!                                                  #
 * ####################################################################
 *
 * There is no strict promise about the base, although it tends to start
 * at 0 on boot (but people really shouldn't rely on that).
 *
 * cpu_clock(i)       -- can be used from any context, including NMI.
 * sched_clock_cpu(i) -- must be used with local IRQs disabled (implied by NMI)
 * local_clock()      -- is cpu_clock() on the current cpu.
 *
 * How:
 *
 * The implementation either uses sched_clock() when
 * !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK, which means in that case the
 * sched_clock() is assumed to provide these properties (mostly it means
 * the architecture provides a globally synchronized highres time source).
 *
 * Otherwise it tries to create a semi stable clock from a mixture of other
 * clocks, including:
 *
 *  - GTOD (clock monotomic)
 *  - sched_clock()
 *  - explicit idle events
 *
 * We use GTOD as base and use sched_clock() deltas to improve resolution. The
 * deltas are filtered to provide monotonicity and keeping it within an
 * expected window.
 *
 * Furthermore, explicit sleep and wakeup hooks allow us to account for time
 * that is otherwise invisible (TSC gets stopped).
 *
 *
 * Notes:
 *
 * The !IRQ-safetly of sched_clock() and sched_clock_cpu() comes from things
 * like cpufreq interrupts that can change the base clock (TSC) multiplier
 * and cause funny jumps in time -- although the filtering provided by
 * sched_clock_cpu() should mitigate serious artifacts we cannot rely on it
 * in general since for !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK we fully rely on
 * sched_clock().
 */
#include <linux/spinlock.h>
#include <linux/hardirq.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/ktime.h>
#include <linux/sched.h>

/*
 * Scheduler clock - returns current time in nanosec units.
 * This is default implementation.
 * Architectures and sub-architectures can override this.
 */
unsigned long long __attribute__((weak)) sched_clock(void)
{
	return (unsigned long long)(jiffies - INITIAL_JIFFIES)
					* (NSEC_PER_SEC / HZ);
}
EXPORT_SYMBOL_GPL(sched_clock);

__read_mostly int sched_clock_running;

#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
__read_mostly int sched_clock_stable;

struct sched_clock_data {
	u64			tick_raw;
	u64			tick_gtod;
	u64			clock;
};

static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);

static inline struct sched_clock_data *this_scd(void)
{
	return &__get_cpu_var(sched_clock_data);
}

static inline struct sched_clock_data *cpu_sdc(int cpu)
{
	return &per_cpu(sched_clock_data, cpu);
}

void sched_clock_init(void)
{
	u64 ktime_now = ktime_to_ns(ktime_get());
	int cpu;

	for_each_possible_cpu(cpu) {
		struct sched_clock_data *scd = cpu_sdc(cpu);

		scd->tick_raw = 0;
		scd->tick_gtod = ktime_now;
		scd->clock = ktime_now;
	}

	sched_clock_running = 1;
}

/*
 * min, max except they take wrapping into account
 */

static inline u64 wrap_min(u64 x, u64 y)
{
	return (s64)(x - y) < 0 ? x : y;
}

static inline u64 wrap_max(u64 x, u64 y)
{
	return (s64)(x - y) > 0 ? x : y;
}

/*
 * update the percpu scd from the raw @now value
 *
 *  - filter out backward motion
 *  - use the GTOD tick value to create a window to filter crazy TSC values
 */
static u64 sched_clock_local(struct sched_clock_data *scd)
{
	u64 now, clock, old_clock, min_clock, max_clock;
	s64 delta;

again:
	now = sched_clock();
	delta = now - scd->tick_raw;
	if (unlikely(delta < 0))
		delta = 0;

	old_clock = scd->clock;

	/*
	 * scd->clock = clamp(scd->tick_gtod + delta,
	 *		      max(scd->tick_gtod, scd->clock),
	 *		      scd->tick_gtod + TICK_NSEC);
	 */

	clock = scd->tick_gtod + delta;
	min_clock = wrap_max(scd->tick_gtod, old_clock);
	max_clock = wrap_max(old_clock, scd->tick_gtod + TICK_NSEC);

	clock = wrap_max(clock, min_clock);
	clock = wrap_min(clock, max_clock);

	if (cmpxchg64(&scd->clock, old_clock, clock) != old_clock)
		goto again;

	return clock;
}

static u64 sched_clock_remote(struct sched_clock_data *scd)
{
	struct sched_clock_data *my_scd = this_scd();
	u64 this_clock, remote_clock;
	u64 *ptr, old_val, val;

#if BITS_PER_LONG != 64
again:
	/*
	 * Careful here: The local and the remote clock values need to
	 * be read out atomic as we need to compare the values and
	 * then update either the local or the remote side. So the
	 * cmpxchg64 below only protects one readout.
	 *
	 * We must reread via sched_clock_local() in the retry case on
	 * 32bit as an NMI could use sched_clock_local() via the
	 * tracer and hit between the readout of
	 * the low32bit and the high 32bit portion.
	 */
	this_clock = sched_clock_local(my_scd);
	/*
	 * We must enforce atomic readout on 32bit, otherwise the
	 * update on the remote cpu can hit inbetween the readout of
	 * the low32bit and the high 32bit portion.
	 */
	remote_clock = cmpxchg64(&scd->clock, 0, 0);
#else
	/*
	 * On 64bit the read of [my]scd->clock is atomic versus the
	 * update, so we can avoid the above 32bit dance.
	 */
	sched_clock_local(my_scd);
again:
	this_clock = my_scd->clock;
	remote_clock = scd->clock;
#endif

	/*
	 * 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((s64)(remote_clock - this_clock) < 0)) {
		ptr = &scd->clock;
		old_val = remote_clock;
		val = this_clock;
	} else {
		/*
		 * Should be rare, but possible:
		 */
		ptr = &my_scd->clock;
		old_val = this_clock;
		val = remote_clock;
	}

	if (cmpxchg64(ptr, old_val, val) != old_val)
		goto again;

	return val;
}

/*
 * Similar to cpu_clock(), but requires local IRQs to be disabled.
 *
 * See cpu_clock().
 */
u64 sched_clock_cpu(int cpu)
{
	struct sched_clock_data *scd;
	u64 clock;

	WARN_ON_ONCE(!irqs_disabled());

	if (sched_clock_stable)
		return sched_clock();

	if (unlikely(!sched_clock_running))
		return 0ull;

	scd = cpu_sdc(cpu);

	if (cpu != smp_processor_id())
		clock = sched_clock_remote(scd);
	else
		clock = sched_clock_local(scd);

	return clock;
}

void sched_clock_tick(void)
{
	struct sched_clock_data *scd;
	u64 now, now_gtod;

	if (sched_clock_stable)
		return;

	if (unlikely(!sched_clock_running))
		return;

	WARN_ON_ONCE(!irqs_disabled());

	scd = this_scd();
	now_gtod = ktime_to_ns(ktime_get());
	now = sched_clock();

	scd->tick_raw = now;
	scd->tick_gtod = now_gtod;
	sched_clock_local(scd);
}

/*
 * We are going deep-idle (irqs are disabled):
 */
void sched_clock_idle_sleep_event(void)
{
	sched_clock_cpu(smp_processor_id());
}
EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);

/*
 * We just idled delta nanoseconds (called with irqs disabled):
 */
void sched_clock_idle_wakeup_event(u64 delta_ns)
{
	if (timekeeping_suspended)
		return;

	sched_clock_tick();
	touch_softlockup_watchdog();
}
EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);

/*
 * As outlined at the top, provides a fast, high resolution, nanosecond
 * time source that is monotonic per cpu argument and has bounded drift
 * between cpus.
 *
 * ######################### BIG FAT WARNING ##########################
 * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
 * # go backwards !!                                                  #
 * ####################################################################
 */
u64 cpu_clock(int cpu)
{
	u64 clock;
	unsigned long flags;

	local_irq_save(flags);
	clock = sched_clock_cpu(cpu);
	local_irq_restore(flags);

	return clock;
}

/*
 * Similar to cpu_clock() for the current cpu. Time will only be observed
 * to be monotonic if care is taken to only compare timestampt taken on the
 * same CPU.
 *
 * See cpu_clock().
 */
u64 local_clock(void)
{
	u64 clock;
	unsigned long flags;

	local_irq_save(flags);
	clock = sched_clock_cpu(smp_processor_id());
	local_irq_restore(flags);

	return clock;
}

#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();
}

u64 cpu_clock(int cpu)
{
	return sched_clock_cpu(cpu);
}

u64 local_clock(void)
{
	return sched_clock_cpu(0);
}

#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */

EXPORT_SYMBOL_GPL(cpu_clock);
EXPORT_SYMBOL_GPL(local_clock);
Commit	Line	Data
3e51f33f PZ	1	/*
	2	* sched_clock for unstable cpu clocks
	3	*
	4	* Copyright (C) 2008 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
	5	*
c300ba25 SR	6	* Updates and enhancements:
	7	* Copyright (C) 2008 Red Hat, Inc. Steven Rostedt <srostedt@redhat.com>
	8	*
3e51f33f PZ	9	* Based on code by:
	10	* Ingo Molnar <mingo@redhat.com>
	11	* Guillaume Chazarain <guichaz@gmail.com>
	12	*
c676329a PZ	13	*
	14	* What:
	15	*
	16	* cpu_clock(i) provides a fast (execution time) high resolution
	17	* clock with bounded drift between CPUs. The value of cpu_clock(i)
	18	* is monotonic for constant i. The timestamp returned is in nanoseconds.
	19	*
	20	* ######################### BIG FAT WARNING ##########################
	21	* # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
	22	* # go backwards !! #
	23	* ####################################################################
	24	*
	25	* There is no strict promise about the base, although it tends to start
	26	* at 0 on boot (but people really shouldn't rely on that).
	27	*
	28	* cpu_clock(i) -- can be used from any context, including NMI.
	29	* sched_clock_cpu(i) -- must be used with local IRQs disabled (implied by NMI)
	30	* local_clock() -- is cpu_clock() on the current cpu.
	31	*
	32	* How:
	33	*
	34	* The implementation either uses sched_clock() when
	35	* !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK, which means in that case the
	36	* sched_clock() is assumed to provide these properties (mostly it means
	37	* the architecture provides a globally synchronized highres time source).
	38	*
	39	* Otherwise it tries to create a semi stable clock from a mixture of other
	40	* clocks, including:
	41	*
	42	* - GTOD (clock monotomic)
3e51f33f PZ	43	* - sched_clock()
	44	* - explicit idle events
	45	*
c676329a PZ	46	* We use GTOD as base and use sched_clock() deltas to improve resolution. The
	47	* deltas are filtered to provide monotonicity and keeping it within an
	48	* expected window.
3e51f33f PZ	49	*
	50	* Furthermore, explicit sleep and wakeup hooks allow us to account for time
	51	* that is otherwise invisible (TSC gets stopped).
	52	*
c676329a PZ	53	*
	54	* Notes:
	55	*
	56	* The !IRQ-safetly of sched_clock() and sched_clock_cpu() comes from things
	57	* like cpufreq interrupts that can change the base clock (TSC) multiplier
	58	* and cause funny jumps in time -- although the filtering provided by
	59	* sched_clock_cpu() should mitigate serious artifacts we cannot rely on it
	60	* in general since for !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK we fully rely on
	61	* sched_clock().
3e51f33f	62	*/
3e51f33f	63	#include <linux/spinlock.h>
6409c4da	64	#include <linux/hardirq.h>
9984de1a	65	#include <linux/export.h>
b342501c IM	66	#include <linux/percpu.h>
	67	#include <linux/ktime.h>
	68	#include <linux/sched.h>
3e51f33f	69
2c3d103b HD	70	/*
	71	* Scheduler clock - returns current time in nanosec units.
	72	* This is default implementation.
	73	* Architectures and sub-architectures can override this.
	74	*/
	75	unsigned long long __attribute__((weak)) sched_clock(void)
	76	{
92d23f70 R	77	return (unsigned long long)(jiffies - INITIAL_JIFFIES)
92d23f70 R	78	* (NSEC_PER_SEC / HZ);
2c3d103b	79	}
b6ac23af	80	EXPORT_SYMBOL_GPL(sched_clock);
3e51f33f	81
5bb6b1ea	82	__read_mostly int sched_clock_running;
c1955a3d	83
3e51f33f	84	#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
b342501c	85	__read_mostly int sched_clock_stable;
3e51f33f PZ	86
3e51f33f PZ	87	struct sched_clock_data {
3e51f33f PZ	88	u64 tick_raw;
	89	u64 tick_gtod;
	90	u64 clock;
	91	};
	92
	93	static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
	94
	95	static inline struct sched_clock_data *this_scd(void)
	96	{
	97	return &__get_cpu_var(sched_clock_data);
	98	}
	99
	100	static inline struct sched_clock_data *cpu_sdc(int cpu)
	101	{
	102	return &per_cpu(sched_clock_data, cpu);
	103	}
	104
	105	void sched_clock_init(void)
	106	{
	107	u64 ktime_now = ktime_to_ns(ktime_get());
3e51f33f PZ	108	int cpu;
	109
	110	for_each_possible_cpu(cpu) {
	111	struct sched_clock_data *scd = cpu_sdc(cpu);
	112
a381759d	113	scd->tick_raw = 0;
3e51f33f PZ	114	scd->tick_gtod = ktime_now;
	115	scd->clock = ktime_now;
	116	}
a381759d PZ	117
a381759d PZ	118	sched_clock_running = 1;
3e51f33f PZ	119	}
3e51f33f PZ	120
354879bb	121	/*
b342501c	122	* min, max except they take wrapping into account
354879bb PZ	123	*/
	124
	125	static inline u64 wrap_min(u64 x, u64 y)
	126	{
	127	return (s64)(x - y) < 0 ? x : y;
	128	}
	129
	130	static inline u64 wrap_max(u64 x, u64 y)
	131	{
	132	return (s64)(x - y) > 0 ? x : y;
	133	}
	134
3e51f33f PZ	135	/*
	136	* update the percpu scd from the raw @now value
	137	*
	138	* - filter out backward motion
354879bb	139	* - use the GTOD tick value to create a window to filter crazy TSC values
3e51f33f	140	*/
def0a9b2	141	static u64 sched_clock_local(struct sched_clock_data *scd)
3e51f33f	142	{
def0a9b2 PZ	143	u64 now, clock, old_clock, min_clock, max_clock;
def0a9b2 PZ	144	s64 delta;
3e51f33f	145
def0a9b2 PZ	146	again:
	147	now = sched_clock();
	148	delta = now - scd->tick_raw;
354879bb PZ	149	if (unlikely(delta < 0))
354879bb PZ	150	delta = 0;
3e51f33f	151
def0a9b2 PZ	152	old_clock = scd->clock;
def0a9b2 PZ	153
354879bb PZ	154	/*
354879bb PZ	155	* scd->clock = clamp(scd->tick_gtod + delta,
b342501c IM	156	* max(scd->tick_gtod, scd->clock),
b342501c IM	157	* scd->tick_gtod + TICK_NSEC);
354879bb	158	*/
3e51f33f	159
354879bb	160	clock = scd->tick_gtod + delta;
def0a9b2 PZ	161	min_clock = wrap_max(scd->tick_gtod, old_clock);
def0a9b2 PZ	162	max_clock = wrap_max(old_clock, scd->tick_gtod + TICK_NSEC);
3e51f33f	163
354879bb PZ	164	clock = wrap_max(clock, min_clock);
354879bb PZ	165	clock = wrap_min(clock, max_clock);
3e51f33f	166
152f9d07	167	if (cmpxchg64(&scd->clock, old_clock, clock) != old_clock)
def0a9b2	168	goto again;
56b90612	169
def0a9b2	170	return clock;
3e51f33f PZ	171	}
3e51f33f PZ	172
def0a9b2	173	static u64 sched_clock_remote(struct sched_clock_data *scd)
3e51f33f	174	{
def0a9b2 PZ	175	struct sched_clock_data *my_scd = this_scd();
	176	u64 this_clock, remote_clock;
	177	u64 *ptr, old_val, val;
	178
a1cbcaa9 TG	179	#if BITS_PER_LONG != 64
	180	again:
	181	/*
	182	* Careful here: The local and the remote clock values need to
	183	* be read out atomic as we need to compare the values and
	184	* then update either the local or the remote side. So the
	185	* cmpxchg64 below only protects one readout.
	186	*
	187	* We must reread via sched_clock_local() in the retry case on
	188	* 32bit as an NMI could use sched_clock_local() via the
	189	* tracer and hit between the readout of
	190	* the low32bit and the high 32bit portion.
	191	*/
	192	this_clock = sched_clock_local(my_scd);
	193	/*
	194	* We must enforce atomic readout on 32bit, otherwise the
	195	* update on the remote cpu can hit inbetween the readout of
	196	* the low32bit and the high 32bit portion.
	197	*/
	198	remote_clock = cmpxchg64(&scd->clock, 0, 0);
	199	#else
	200	/*
	201	* On 64bit the read of [my]scd->clock is atomic versus the
	202	* update, so we can avoid the above 32bit dance.
	203	*/
def0a9b2 PZ	204	sched_clock_local(my_scd);
	205	again:
	206	this_clock = my_scd->clock;
	207	remote_clock = scd->clock;
a1cbcaa9	208	#endif
def0a9b2 PZ	209
	210	/*
	211	* Use the opportunity that we have both locks
	212	* taken to couple the two clocks: we take the
	213	* larger time as the latest time for both
	214	* runqueues. (this creates monotonic movement)
	215	*/
	216	if (likely((s64)(remote_clock - this_clock) < 0)) {
	217	ptr = &scd->clock;
	218	old_val = remote_clock;
	219	val = this_clock;
3e51f33f	220	} else {
def0a9b2 PZ	221	/*
	222	* Should be rare, but possible:
	223	*/
	224	ptr = &my_scd->clock;
	225	old_val = this_clock;
	226	val = remote_clock;
3e51f33f	227	}
def0a9b2	228
152f9d07	229	if (cmpxchg64(ptr, old_val, val) != old_val)
def0a9b2 PZ	230	goto again;
	231
	232	return val;
3e51f33f PZ	233	}
3e51f33f PZ	234
c676329a PZ	235	/*
	236	* Similar to cpu_clock(), but requires local IRQs to be disabled.
	237	*
	238	* See cpu_clock().
	239	*/
3e51f33f PZ	240	u64 sched_clock_cpu(int cpu)
3e51f33f PZ	241	{
b342501c	242	struct sched_clock_data *scd;
def0a9b2 PZ	243	u64 clock;
	244
	245	WARN_ON_ONCE(!irqs_disabled());
3e51f33f	246
b342501c IM	247	if (sched_clock_stable)
b342501c IM	248	return sched_clock();
a381759d	249
a381759d PZ	250	if (unlikely(!sched_clock_running))
	251	return 0ull;
	252
def0a9b2	253	scd = cpu_sdc(cpu);
3e51f33f	254
def0a9b2 PZ	255	if (cpu != smp_processor_id())
	256	clock = sched_clock_remote(scd);
	257	else
	258	clock = sched_clock_local(scd);
e4e4e534	259
3e51f33f PZ	260	return clock;
	261	}
	262
	263	void sched_clock_tick(void)
	264	{
8325d9c0	265	struct sched_clock_data *scd;
3e51f33f PZ	266	u64 now, now_gtod;
3e51f33f PZ	267
8325d9c0 PZ	268	if (sched_clock_stable)
	269	return;
	270
a381759d PZ	271	if (unlikely(!sched_clock_running))
	272	return;
	273
3e51f33f PZ	274	WARN_ON_ONCE(!irqs_disabled());
3e51f33f PZ	275
8325d9c0	276	scd = this_scd();
3e51f33f	277	now_gtod = ktime_to_ns(ktime_get());
a83bc47c	278	now = sched_clock();
3e51f33f	279
3e51f33f PZ	280	scd->tick_raw = now;
3e51f33f PZ	281	scd->tick_gtod = now_gtod;
def0a9b2	282	sched_clock_local(scd);
3e51f33f PZ	283	}
	284
	285	/*
	286	* We are going deep-idle (irqs are disabled):
	287	*/
	288	void sched_clock_idle_sleep_event(void)
	289	{
	290	sched_clock_cpu(smp_processor_id());
	291	}
	292	EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
	293
	294	/*
	295	* We just idled delta nanoseconds (called with irqs disabled):
	296	*/
	297	void sched_clock_idle_wakeup_event(u64 delta_ns)
	298	{
1c5745aa TG	299	if (timekeeping_suspended)
	300	return;
	301
354879bb	302	sched_clock_tick();
3e51f33f PZ	303	touch_softlockup_watchdog();
	304	}
	305	EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
	306
c676329a PZ	307	/*
	308	* As outlined at the top, provides a fast, high resolution, nanosecond
	309	* time source that is monotonic per cpu argument and has bounded drift
	310	* between cpus.
	311	*
	312	* ######################### BIG FAT WARNING ##########################
	313	* # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
	314	* # go backwards !! #
	315	* ####################################################################
	316	*/
	317	u64 cpu_clock(int cpu)
b9f8fcd5	318	{
c676329a	319	u64 clock;
b9f8fcd5 DM	320	unsigned long flags;
	321
	322	local_irq_save(flags);
	323	clock = sched_clock_cpu(cpu);
	324	local_irq_restore(flags);
	325
	326	return clock;
	327	}
	328
c676329a PZ	329	/*
	330	* Similar to cpu_clock() for the current cpu. Time will only be observed
	331	* to be monotonic if care is taken to only compare timestampt taken on the
	332	* same CPU.
	333	*
	334	* See cpu_clock().
	335	*/
	336	u64 local_clock(void)
	337	{
	338	u64 clock;
	339	unsigned long flags;
	340
	341	local_irq_save(flags);
	342	clock = sched_clock_cpu(smp_processor_id());
	343	local_irq_restore(flags);
	344
	345	return clock;
	346	}
	347
8325d9c0 PZ	348	#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
	349
	350	void sched_clock_init(void)
	351	{
	352	sched_clock_running = 1;
	353	}
	354
	355	u64 sched_clock_cpu(int cpu)
	356	{
	357	if (unlikely(!sched_clock_running))
	358	return 0;
	359
	360	return sched_clock();
	361	}
	362
c676329a	363	u64 cpu_clock(int cpu)
76a2a6ee	364	{
b9f8fcd5 DM	365	return sched_clock_cpu(cpu);
b9f8fcd5 DM	366	}
76a2a6ee	367
c676329a PZ	368	u64 local_clock(void)
	369	{
	370	return sched_clock_cpu(0);
	371	}
	372
b9f8fcd5	373	#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
76a2a6ee	374
4c9fe8ad	375	EXPORT_SYMBOL_GPL(cpu_clock);
c676329a	376	EXPORT_SYMBOL_GPL(local_clock);