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author | john stultz <johnstul@us.ibm.com> | 2007-02-16 01:27:26 -0800 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-16 08:13:56 -0800 |
commit | f4304ab21513b834c8fe3403927c60c2b81a72d7 (patch) | |
tree | 212c8fa327d9cf3f29cccf172f0707a3eb6524f8 | |
parent | 771ee3b04eaac6184312825eb600b4c598f027a5 (diff) | |
download | linux-stable-f4304ab21513b834c8fe3403927c60c2b81a72d7.tar.gz linux-stable-f4304ab21513b834c8fe3403927c60c2b81a72d7.tar.bz2 linux-stable-f4304ab21513b834c8fe3403927c60c2b81a72d7.zip |
[PATCH] HZ free ntp
Distangle the NTP update from HZ. This is necessary for dynamic tick enabled
kernels.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | include/linux/timex.h | 7 | ||||
-rw-r--r-- | kernel/hrtimer.c | 11 | ||||
-rw-r--r-- | kernel/time/ntp.c | 30 | ||||
-rw-r--r-- | kernel/timer.c | 4 |
4 files changed, 36 insertions, 16 deletions
diff --git a/include/linux/timex.h b/include/linux/timex.h index 9a24e500c311..da929dbbea2a 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -286,6 +286,13 @@ static inline void time_interpolator_update(long delta_nsec) #define TICK_LENGTH_SHIFT 32 +#ifdef CONFIG_NO_HZ +#define NTP_INTERVAL_FREQ (2) +#else +#define NTP_INTERVAL_FREQ (HZ) +#endif +#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ) + /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */ extern u64 current_tick_length(void); diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index f44e499e8fca..80666f6cd4f9 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -128,15 +128,20 @@ EXPORT_SYMBOL_GPL(ktime_get_ts); static void hrtimer_get_softirq_time(struct hrtimer_base *base) { ktime_t xtim, tomono; + struct timespec xts; unsigned long seq; do { seq = read_seqbegin(&xtime_lock); - xtim = timespec_to_ktime(xtime); - tomono = timespec_to_ktime(wall_to_monotonic); - +#ifdef CONFIG_NO_HZ + getnstimeofday(&xts); +#else + xts = xtime; +#endif } while (read_seqretry(&xtime_lock, seq)); + xtim = timespec_to_ktime(xts); + tomono = timespec_to_ktime(wall_to_monotonic); base[CLOCK_REALTIME].softirq_time = xtim; base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono); } diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 3afeaa3a73f9..eb12509e00bd 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -24,7 +24,7 @@ static u64 tick_length, tick_length_base; #define MAX_TICKADJ 500 /* microsecs */ #define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \ - TICK_LENGTH_SHIFT) / HZ) + TICK_LENGTH_SHIFT) / NTP_INTERVAL_FREQ) /* * phase-lock loop variables @@ -46,13 +46,17 @@ long time_adjust; static void ntp_update_frequency(void) { - tick_length_base = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) << TICK_LENGTH_SHIFT; - tick_length_base += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT; - tick_length_base += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC); + u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) + << TICK_LENGTH_SHIFT; + second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT; + second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC); - do_div(tick_length_base, HZ); + tick_length_base = second_length; - tick_nsec = tick_length_base >> TICK_LENGTH_SHIFT; + do_div(second_length, HZ); + tick_nsec = second_length >> TICK_LENGTH_SHIFT; + + do_div(tick_length_base, NTP_INTERVAL_FREQ); } /** @@ -162,7 +166,7 @@ void second_overflow(void) tick_length -= MAX_TICKADJ_SCALED; } else { tick_length += (s64)(time_adjust * NSEC_PER_USEC / - HZ) << TICK_LENGTH_SHIFT; + NTP_INTERVAL_FREQ) << TICK_LENGTH_SHIFT; time_adjust = 0; } } @@ -239,7 +243,8 @@ int do_adjtimex(struct timex *txc) result = -EINVAL; goto leave; } - time_freq = ((s64)txc->freq * NSEC_PER_USEC) >> (SHIFT_USEC - SHIFT_NSEC); + time_freq = ((s64)txc->freq * NSEC_PER_USEC) + >> (SHIFT_USEC - SHIFT_NSEC); } if (txc->modes & ADJ_MAXERROR) { @@ -309,7 +314,8 @@ int do_adjtimex(struct timex *txc) freq_adj += time_freq; freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC); time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC); - time_offset = (time_offset / HZ) << SHIFT_UPDATE; + time_offset = (time_offset / NTP_INTERVAL_FREQ) + << SHIFT_UPDATE; } /* STA_PLL */ } /* txc->modes & ADJ_OFFSET */ if (txc->modes & ADJ_TICK) @@ -324,8 +330,10 @@ leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0) if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) txc->offset = save_adjust; else - txc->offset = shift_right(time_offset, SHIFT_UPDATE) * HZ / 1000; - txc->freq = (time_freq / NSEC_PER_USEC) << (SHIFT_USEC - SHIFT_NSEC); + txc->offset = shift_right(time_offset, SHIFT_UPDATE) + * NTP_INTERVAL_FREQ / 1000; + txc->freq = (time_freq / NSEC_PER_USEC) + << (SHIFT_USEC - SHIFT_NSEC); txc->maxerror = time_maxerror; txc->esterror = time_esterror; txc->status = time_status; diff --git a/kernel/timer.c b/kernel/timer.c index 4902181e10e6..4f9cc2a48beb 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -890,7 +890,7 @@ void __init timekeeping_init(void) ntp_clear(); clock = clocksource_get_next(); - clocksource_calculate_interval(clock, tick_nsec); + clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); clock->cycle_last = clocksource_read(clock); write_sequnlock_irqrestore(&xtime_lock, flags); @@ -1092,7 +1092,7 @@ static void update_wall_time(void) if (change_clocksource()) { clock->error = 0; clock->xtime_nsec = 0; - clocksource_calculate_interval(clock, tick_nsec); + clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); } } |