linux-sg2042/kernel/time
Miroslav Lichvar 8af3c153ba ntp: Clamp PLL update interval
Clamp update interval to reduce PLL gain with low sampling rate (e.g.
intermittent network connection) to avoid instability.

The clamp roughly corresponds to the loop time constant, it's 8 * poll
interval for SHIFT_PLL 2 and 32 * poll interval for SHIFT_PLL 4. This
gives good results without affecting the gain in normal conditions where
ntpd skips only up to seven consecutive samples.

Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Acked-by: john stultz <johnstul@us.ibm.com>
LKML-Reference: <1283870626-9472-1-git-send-email-mlichvar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-09-09 20:48:37 +02:00
..
Kconfig time: Kill off CONFIG_GENERIC_TIME 2010-07-27 12:40:54 +02:00
Makefile time: add function to convert between calendar time and broken-down time for universal use 2009-09-24 07:20:56 -07:00
clockevents.c clockevent: Don't remove broadcast device when cpu is dead 2010-01-18 14:44:50 +01:00
clocksource.c clocksource: Add __clocksource_updatefreq_hz/khz methods 2010-07-27 12:40:55 +02:00
jiffies.c clocksource: Cleanup clocksource selection 2009-08-15 10:55:46 +02:00
ntp.c ntp: Clamp PLL update interval 2010-09-09 20:48:37 +02:00
tick-broadcast.c fix comment/printk typos concerning "already" 2010-07-11 21:45:40 +02:00
tick-common.c clockevents: Convert to raw_spinlock 2009-12-14 23:55:34 +01:00
tick-internal.h clockevents: Make tick_device_lock static 2009-12-14 23:55:34 +01:00
tick-oneshot.c clockevents: Sanitize min_delta_ns adjustment and prevent overflows 2010-03-12 19:10:29 +01:00
tick-sched.c Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 13:12:36 -07:00
timecompare.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
timeconv.c time: add function to convert between calendar time and broken-down time for universal use 2009-09-24 07:20:56 -07:00
timekeeping.c time: Workaround gcc loop optimization that causes 64bit div errors 2010-08-13 12:03:24 -07:00
timer_list.c sched: Intoduce get_cpu_iowait_time_us() 2010-05-09 19:35:27 +02:00
timer_stats.c hrtimers: Convert to raw_spinlocks 2009-12-14 23:55:34 +01:00