Commit e26b33e9 authored by Ingo Molnar's avatar Ingo Molnar

Merge branch 'sched/clock' into sched/urgent

parents 279ef6bb cf206bff
...@@ -1551,16 +1551,10 @@ static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) ...@@ -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); extern unsigned long long sched_clock(void);
#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK extern void sched_clock_init(void);
static inline void sched_clock_init(void) extern u64 sched_clock_cpu(int cpu);
{
}
static inline u64 sched_clock_cpu(int cpu)
{
return sched_clock();
}
#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
static inline void sched_clock_tick(void) static inline void sched_clock_tick(void)
{ {
} }
...@@ -1572,28 +1566,11 @@ static inline void sched_clock_idle_sleep_event(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) static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
{ {
} }
#else
#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);
extern void sched_clock_tick(void); extern void sched_clock_tick(void);
extern void sched_clock_idle_sleep_event(void); extern void sched_clock_idle_sleep_event(void);
extern void sched_clock_idle_wakeup_event(u64 delta_ns); 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
#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
/* /*
* For kernel-internal use: high-speed (but slightly incorrect) per-cpu * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
......
...@@ -42,12 +42,9 @@ unsigned long long __attribute__((weak)) sched_clock(void) ...@@ -42,12 +42,9 @@ unsigned long long __attribute__((weak)) sched_clock(void)
return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); 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 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
/* Max is double, Min is 1/2 */
#define MAX_MULTI (2LL << MULTI_SHIFT)
#define MIN_MULTI (1LL << (MULTI_SHIFT-1))
struct sched_clock_data { struct sched_clock_data {
/* /*
...@@ -58,14 +55,9 @@ struct sched_clock_data { ...@@ -58,14 +55,9 @@ struct sched_clock_data {
raw_spinlock_t lock; raw_spinlock_t lock;
unsigned long tick_jiffies; unsigned long tick_jiffies;
u64 prev_raw;
u64 tick_raw; u64 tick_raw;
u64 tick_gtod; u64 tick_gtod;
u64 clock; 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); 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) ...@@ -80,8 +72,6 @@ static inline struct sched_clock_data *cpu_sdc(int cpu)
return &per_cpu(sched_clock_data, cpu); return &per_cpu(sched_clock_data, cpu);
} }
static __read_mostly int sched_clock_running;
void sched_clock_init(void) void sched_clock_init(void)
{ {
u64 ktime_now = ktime_to_ns(ktime_get()); u64 ktime_now = ktime_to_ns(ktime_get());
...@@ -93,90 +83,39 @@ void sched_clock_init(void) ...@@ -93,90 +83,39 @@ void sched_clock_init(void)
scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
scd->tick_jiffies = now_jiffies; scd->tick_jiffies = now_jiffies;
scd->prev_raw = 0;
scd->tick_raw = 0; scd->tick_raw = 0;
scd->tick_gtod = ktime_now; scd->tick_gtod = ktime_now;
scd->clock = ktime_now; scd->clock = ktime_now;
scd->multi = 1 << MULTI_SHIFT;
#ifdef CONFIG_NO_HZ
scd->check_max = 1;
#endif
} }
sched_clock_running = 1; 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 * update the percpu scd from the raw @now value
* *
* - filter out backward motion * - filter out backward motion
* - use jiffies to generate a min,max window to clip the raw values * - 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; unsigned long now_jiffies = jiffies;
long delta_jiffies = now_jiffies - scd->tick_jiffies; long delta_jiffies = now_jiffies - scd->tick_jiffies;
u64 clock = scd->clock; u64 clock = scd->clock;
u64 min_clock, max_clock; u64 min_clock, max_clock;
s64 delta = now - scd->prev_raw; s64 delta = now - scd->tick_raw;
WARN_ON_ONCE(!irqs_disabled()); WARN_ON_ONCE(!irqs_disabled());
min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC;
/*
* 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;
if (unlikely(delta < 0)) { if (unlikely(delta < 0)) {
clock++; clock++;
goto out; goto out;
} }
/* max_clock = min_clock + TICK_NSEC;
* 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;
if (unlikely(clock + delta > max_clock) && check_max(scd)) { if (unlikely(clock + delta > max_clock)) {
if (clock < max_clock) if (clock < max_clock)
clock = max_clock; clock = max_clock;
else else
...@@ -189,12 +128,10 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim ...@@ -189,12 +128,10 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim
if (unlikely(clock < min_clock)) if (unlikely(clock < min_clock))
clock = min_clock; clock = min_clock;
if (time) scd->tick_jiffies = now_jiffies;
*time = clock;
else {
scd->prev_raw = now;
scd->clock = clock; scd->clock = clock;
}
return clock;
} }
static void lock_double_clock(struct sched_clock_data *data1, static void lock_double_clock(struct sched_clock_data *data1,
...@@ -212,7 +149,7 @@ 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) u64 sched_clock_cpu(int cpu)
{ {
struct sched_clock_data *scd = cpu_sdc(cpu); struct sched_clock_data *scd = cpu_sdc(cpu);
u64 now, clock; u64 now, clock, this_clock, remote_clock;
if (unlikely(!sched_clock_running)) if (unlikely(!sched_clock_running))
return 0ull; return 0ull;
...@@ -221,43 +158,44 @@ u64 sched_clock_cpu(int cpu) ...@@ -221,43 +158,44 @@ u64 sched_clock_cpu(int cpu)
now = sched_clock(); now = sched_clock();
if (cpu != raw_smp_processor_id()) { 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(); struct sched_clock_data *my_scd = this_scd();
lock_double_clock(scd, my_scd); lock_double_clock(scd, my_scd);
now -= my_scd->tick_raw; this_clock = __update_sched_clock(my_scd, now);
now += scd->tick_raw; 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); __raw_spin_unlock(&my_scd->lock);
__update_sched_clock(scd, now, &clock);
__raw_spin_unlock(&scd->lock);
} else { } else {
__raw_spin_lock(&scd->lock); __raw_spin_lock(&scd->lock);
__update_sched_clock(scd, now, NULL); clock = __update_sched_clock(scd, now);
clock = scd->clock;
__raw_spin_unlock(&scd->lock);
} }
__raw_spin_unlock(&scd->lock);
return clock; return clock;
} }
void sched_clock_tick(void) void sched_clock_tick(void)
{ {
struct sched_clock_data *scd = this_scd(); struct sched_clock_data *scd = this_scd();
unsigned long now_jiffies = jiffies;
s64 mult, delta_gtod, delta_raw;
u64 now, now_gtod; u64 now, now_gtod;
if (unlikely(!sched_clock_running)) if (unlikely(!sched_clock_running))
...@@ -269,29 +207,14 @@ void sched_clock_tick(void) ...@@ -269,29 +207,14 @@ void sched_clock_tick(void)
now = sched_clock(); now = sched_clock();
__raw_spin_lock(&scd->lock); __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 * update tick_gtod after __update_sched_clock() because that will
* already observe 1 new jiffy; adding a new tick_gtod to that would * already observe 1 new jiffy; adding a new tick_gtod to that would
* increase the clock 2 jiffies. * 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_raw = now;
scd->tick_gtod = now_gtod; scd->tick_gtod = now_gtod;
scd->tick_jiffies = now_jiffies;
__raw_spin_unlock(&scd->lock); __raw_spin_unlock(&scd->lock);
} }
...@@ -310,7 +233,6 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); ...@@ -310,7 +233,6 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
void sched_clock_idle_wakeup_event(u64 delta_ns) void sched_clock_idle_wakeup_event(u64 delta_ns)
{ {
struct sched_clock_data *scd = this_scd(); struct sched_clock_data *scd = this_scd();
u64 now = sched_clock();
/* /*
* Override the previous timestamp and ignore all * Override the previous timestamp and ignore all
...@@ -319,15 +241,28 @@ void sched_clock_idle_wakeup_event(u64 delta_ns) ...@@ -319,15 +241,28 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
* rq clock: * rq clock:
*/ */
__raw_spin_lock(&scd->lock); __raw_spin_lock(&scd->lock);
scd->prev_raw = now;
scd->clock += delta_ns; scd->clock += delta_ns;
scd->multi = 1 << MULTI_SHIFT;
__raw_spin_unlock(&scd->lock); __raw_spin_unlock(&scd->lock);
touch_softlockup_watchdog(); touch_softlockup_watchdog();
} }
EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); 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 #endif
unsigned long long cpu_clock(int cpu) unsigned long long cpu_clock(int cpu)
......
...@@ -289,7 +289,6 @@ void tick_nohz_stop_sched_tick(int inidle) ...@@ -289,7 +289,6 @@ void tick_nohz_stop_sched_tick(int inidle)
ts->tick_stopped = 1; ts->tick_stopped = 1;
ts->idle_jiffies = last_jiffies; ts->idle_jiffies = last_jiffies;
rcu_enter_nohz(); rcu_enter_nohz();
sched_clock_tick_stop(cpu);
} }
/* /*
...@@ -392,7 +391,6 @@ void tick_nohz_restart_sched_tick(void) ...@@ -392,7 +391,6 @@ void tick_nohz_restart_sched_tick(void)
select_nohz_load_balancer(0); select_nohz_load_balancer(0);
now = ktime_get(); now = ktime_get();
tick_do_update_jiffies64(now); tick_do_update_jiffies64(now);
sched_clock_tick_start(cpu);
cpu_clear(cpu, nohz_cpu_mask); cpu_clear(cpu, nohz_cpu_mask);
/* /*
......
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