diff options
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/clocksource.c | 48 | ||||
| -rw-r--r-- | kernel/time/ntp.c | 2 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 84 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 35 | ||||
| -rw-r--r-- | kernel/time/timer_list.c | 1 |
5 files changed, 136 insertions, 34 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 1f5dde63745..f08e99c1d56 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -625,6 +625,54 @@ static void clocksource_enqueue(struct clocksource *cs) list_add(&cs->list, entry); } + +/* + * Maximum time we expect to go between ticks. This includes idle + * tickless time. It provides the trade off between selecting a + * mult/shift pair that is very precise but can only handle a short + * period of time, vs. a mult/shift pair that can handle long periods + * of time but isn't as precise. + * + * This is a subsystem constant, and actual hardware limitations + * may override it (ie: clocksources that wrap every 3 seconds). + */ +#define MAX_UPDATE_LENGTH 5 /* Seconds */ + +/** + * __clocksource_register_scale - Used to install new clocksources + * @t: clocksource to be registered + * @scale: Scale factor multiplied against freq to get clocksource hz + * @freq: clocksource frequency (cycles per second) divided by scale + * + * Returns -EBUSY if registration fails, zero otherwise. + * + * This *SHOULD NOT* be called directly! Please use the + * clocksource_register_hz() or clocksource_register_khz helper functions. + */ +int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) +{ + + /* + * Ideally we want to use some of the limits used in + * clocksource_max_deferment, to provide a more informed + * MAX_UPDATE_LENGTH. But for now this just gets the + * register interface working properly. + */ + clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, + NSEC_PER_SEC/scale, + MAX_UPDATE_LENGTH*scale); + cs->max_idle_ns = clocksource_max_deferment(cs); + + mutex_lock(&clocksource_mutex); + clocksource_enqueue(cs); + clocksource_select(); + clocksource_enqueue_watchdog(cs); + mutex_unlock(&clocksource_mutex); + return 0; +} +EXPORT_SYMBOL_GPL(__clocksource_register_scale); + + /** * clocksource_register - Used to install new clocksources * @t: clocksource to be registered diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 7c0f180d6e9..c63116863a8 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -69,7 +69,7 @@ static s64 time_freq; /* time at last adjustment (secs): */ static long time_reftime; -long time_adjust; +static long time_adjust; /* constant (boot-param configurable) NTP tick adjustment (upscaled) */ static s64 ntp_tick_adj; diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index f992762d7f5..1d7b9bc1c03 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -150,14 +150,32 @@ static void tick_nohz_update_jiffies(ktime_t now) touch_softlockup_watchdog(); } +/* + * Updates the per cpu time idle statistics counters + */ +static void +update_ts_time_stats(struct tick_sched *ts, ktime_t now, u64 *last_update_time) +{ + ktime_t delta; + + if (ts->idle_active) { + delta = ktime_sub(now, ts->idle_entrytime); + ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); + if (nr_iowait_cpu() > 0) + ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta); + ts->idle_entrytime = now; + } + + if (last_update_time) + *last_update_time = ktime_to_us(now); + +} + static void tick_nohz_stop_idle(int cpu, ktime_t now) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); - ktime_t delta; - delta = ktime_sub(now, ts->idle_entrytime); - ts->idle_lastupdate = now; - ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); + update_ts_time_stats(ts, now, NULL); ts->idle_active = 0; sched_clock_idle_wakeup_event(0); @@ -165,20 +183,32 @@ static void tick_nohz_stop_idle(int cpu, ktime_t now) static ktime_t tick_nohz_start_idle(struct tick_sched *ts) { - ktime_t now, delta; + ktime_t now; now = ktime_get(); - if (ts->idle_active) { - delta = ktime_sub(now, ts->idle_entrytime); - ts->idle_lastupdate = now; - ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); - } + + update_ts_time_stats(ts, now, NULL); + ts->idle_entrytime = now; ts->idle_active = 1; sched_clock_idle_sleep_event(); return now; } +/** + * get_cpu_idle_time_us - get the total idle time of a cpu + * @cpu: CPU number to query + * @last_update_time: variable to store update time in + * + * Return the cummulative idle time (since boot) for a given + * CPU, in microseconds. The idle time returned includes + * the iowait time (unlike what "top" and co report). + * + * This time is measured via accounting rather than sampling, + * and is as accurate as ktime_get() is. + * + * This function returns -1 if NOHZ is not enabled. + */ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); @@ -186,15 +216,38 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) if (!tick_nohz_enabled) return -1; - if (ts->idle_active) - *last_update_time = ktime_to_us(ts->idle_lastupdate); - else - *last_update_time = ktime_to_us(ktime_get()); + update_ts_time_stats(ts, ktime_get(), last_update_time); return ktime_to_us(ts->idle_sleeptime); } EXPORT_SYMBOL_GPL(get_cpu_idle_time_us); +/* + * get_cpu_iowait_time_us - get the total iowait time of a cpu + * @cpu: CPU number to query + * @last_update_time: variable to store update time in + * + * Return the cummulative iowait time (since boot) for a given + * CPU, in microseconds. + * + * This time is measured via accounting rather than sampling, + * and is as accurate as ktime_get() is. + * + * This function returns -1 if NOHZ is not enabled. + */ +u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time) +{ + struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); + + if (!tick_nohz_enabled) + return -1; + + update_ts_time_stats(ts, ktime_get(), last_update_time); + + return ktime_to_us(ts->iowait_sleeptime); +} +EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us); + /** * tick_nohz_stop_sched_tick - stop the idle tick from the idle task * @@ -262,6 +315,9 @@ void tick_nohz_stop_sched_tick(int inidle) goto end; } + if (nohz_ratelimit(cpu)) + goto end; + ts->idle_calls++; /* Read jiffies and the time when jiffies were updated last */ do { diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 39f6177fafa..caf8d4d4f5c 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -165,13 +165,6 @@ struct timespec raw_time; /* flag for if timekeeping is suspended */ int __read_mostly timekeeping_suspended; -static struct timespec xtime_cache __attribute__ ((aligned (16))); -void update_xtime_cache(u64 nsec) -{ - xtime_cache = xtime; - timespec_add_ns(&xtime_cache, nsec); -} - /* must hold xtime_lock */ void timekeeping_leap_insert(int leapsecond) { @@ -332,8 +325,6 @@ int do_settimeofday(struct timespec *tv) xtime = *tv; - update_xtime_cache(0); - timekeeper.ntp_error = 0; ntp_clear(); @@ -559,7 +550,6 @@ void __init timekeeping_init(void) } set_normalized_timespec(&wall_to_monotonic, -boot.tv_sec, -boot.tv_nsec); - update_xtime_cache(0); total_sleep_time.tv_sec = 0; total_sleep_time.tv_nsec = 0; write_sequnlock_irqrestore(&xtime_lock, flags); @@ -593,7 +583,6 @@ static int timekeeping_resume(struct sys_device *dev) wall_to_monotonic = timespec_sub(wall_to_monotonic, ts); total_sleep_time = timespec_add_safe(total_sleep_time, ts); } - update_xtime_cache(0); /* re-base the last cycle value */ timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); timekeeper.ntp_error = 0; @@ -788,7 +777,6 @@ void update_wall_time(void) { struct clocksource *clock; cycle_t offset; - u64 nsecs; int shift = 0, maxshift; /* Make sure we're fully resumed: */ @@ -847,7 +835,9 @@ void update_wall_time(void) timekeeper.ntp_error += neg << timekeeper.ntp_error_shift; } - /* store full nanoseconds into xtime after rounding it up and + + /* + * Store full nanoseconds into xtime after rounding it up and * add the remainder to the error difference. */ xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1; @@ -855,8 +845,15 @@ void update_wall_time(void) timekeeper.ntp_error += timekeeper.xtime_nsec << timekeeper.ntp_error_shift; - nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift); - update_xtime_cache(nsecs); + /* + * Finally, make sure that after the rounding + * xtime.tv_nsec isn't larger then NSEC_PER_SEC + */ + if (unlikely(xtime.tv_nsec >= NSEC_PER_SEC)) { + xtime.tv_nsec -= NSEC_PER_SEC; + xtime.tv_sec++; + second_overflow(); + } /* check to see if there is a new clocksource to use */ update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); @@ -896,13 +893,13 @@ EXPORT_SYMBOL_GPL(monotonic_to_bootbased); unsigned long get_seconds(void) { - return xtime_cache.tv_sec; + return xtime.tv_sec; } EXPORT_SYMBOL(get_seconds); struct timespec __current_kernel_time(void) { - return xtime_cache; + return xtime; } struct timespec current_kernel_time(void) @@ -913,7 +910,7 @@ struct timespec current_kernel_time(void) do { seq = read_seqbegin(&xtime_lock); - now = xtime_cache; + now = xtime; } while (read_seqretry(&xtime_lock, seq)); return now; @@ -928,7 +925,7 @@ struct timespec get_monotonic_coarse(void) do { seq = read_seqbegin(&xtime_lock); - now = xtime_cache; + now = xtime; mono = wall_to_monotonic; } while (read_seqretry(&xtime_lock, seq)); diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index 1a4a7dd7877..ab8f5e33fa9 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -176,6 +176,7 @@ static void print_cpu(struct seq_file *m, int cpu, u64 now) P_ns(idle_waketime); P_ns(idle_exittime); P_ns(idle_sleeptime); + P_ns(iowait_sleeptime); P(last_jiffies); P(next_jiffies); P_ns(idle_expires); |