From af5ca3f4ec5cc4432a42a73b050dd8898ce8fd00 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Thu, 20 Dec 2007 02:09:39 +0100 Subject: Driver core: change sysdev classes to use dynamic kobject names All kobjects require a dynamically allocated name now. We no longer need to keep track if the name is statically assigned, we can just unconditionally free() all kobject names on cleanup. Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- kernel/time/timekeeping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/time/timekeeping.c') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index e5e466b27598..ab46ae8c062b 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -335,9 +335,9 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) /* sysfs resume/suspend bits for timekeeping */ static struct sysdev_class timekeeping_sysclass = { + .name = "timekeeping", .resume = timekeeping_resume, .suspend = timekeeping_suspend, - set_kset_name("timekeeping"), }; static struct sys_device device_timer = { -- cgit v1.2.3 From efd9ac8630e89b9ee7ce64008bd7783952374f37 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 30 Jan 2008 13:30:01 +0100 Subject: time: fold __get_realtime_clock_ts() into getnstimeofday() - getnstimeofday() was just a wrapper around __get_realtime_clock_ts() - Replace calls to __get_realtime_clock_ts() by calls to getnstimeofday() - Fix bogus reference to get_realtime_clock_ts(), which never existed Signed-off-by: Geert Uytterhoeven Cc: john stultz Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/time/timekeeping.c | 22 +++++----------------- 1 file changed, 5 insertions(+), 17 deletions(-) (limited to 'kernel/time/timekeeping.c') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index ab46ae8c062b..77680195cf84 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -82,13 +82,12 @@ static inline s64 __get_nsec_offset(void) } /** - * __get_realtime_clock_ts - Returns the time of day in a timespec + * getnstimeofday - Returns the time of day in a timespec * @ts: pointer to the timespec to be set * - * Returns the time of day in a timespec. Used by - * do_gettimeofday() and get_realtime_clock_ts(). + * Returns the time of day in a timespec. */ -static inline void __get_realtime_clock_ts(struct timespec *ts) +void getnstimeofday(struct timespec *ts) { unsigned long seq; s64 nsecs; @@ -104,30 +103,19 @@ static inline void __get_realtime_clock_ts(struct timespec *ts) timespec_add_ns(ts, nsecs); } -/** - * getnstimeofday - Returns the time of day in a timespec - * @ts: pointer to the timespec to be set - * - * Returns the time of day in a timespec. - */ -void getnstimeofday(struct timespec *ts) -{ - __get_realtime_clock_ts(ts); -} - EXPORT_SYMBOL(getnstimeofday); /** * do_gettimeofday - Returns the time of day in a timeval * @tv: pointer to the timeval to be set * - * NOTE: Users should be converted to using get_realtime_clock_ts() + * NOTE: Users should be converted to using getnstimeofday() */ void do_gettimeofday(struct timeval *tv) { struct timespec now; - __get_realtime_clock_ts(&now); + getnstimeofday(&now); tv->tv_sec = now.tv_sec; tv->tv_usec = now.tv_nsec/1000; } -- cgit v1.2.3 From bbe4d18ac2e058c56adb0cd71f49d9ed3216a405 Mon Sep 17 00:00:00 2001 From: john stultz Date: Wed, 30 Jan 2008 13:30:03 +0100 Subject: NTP: correct inconsistent ntp interval/tick_length usage I recently noticed on one of my boxes that when synched with an NTP server, the drift value reported for the system was ~283ppm. While in some cases, clock hardware can be that bad, it struck me as unusual as the system was using the acpi_pm clocksource, which is one of the more trustworthy and accurate clocksources on x86 hardware. I brought up another system and let it sync to the same NTP server, and I noticed a similar 280some ppm drift. In looking at the code, I found that the acpi_pm's constant frequency was being computed correctly at boot-up, however once the system was up, even without the ntp daemon running, the clocksource's frequency was being modified by the clocksource_adjust() function. Digging deeper, I realized that in the code that keeps track of how much the clocksource is skewing from the ntp desired time, we were using different lengths to establish how long an time interval was. The clocksource was being setup with the following interval: NTP_INTERVAL_LENGTH = NSEC_PER_SEC/NTP_INTERVAL_FREQ While the ntp code was using the tick_length_base value: tick_length_base ~= (tick_usec * NSEC_PER_USEC * USER_HZ) /NTP_INTERVAL_FREQ The subtle difference is: (tick_usec * NSEC_PER_USEC * USER_HZ) != NSEC_PER_SEC This difference in calculation was causing the clocksource correction code to apply a correction factor to the clocksource so the two intervals were the same, however this results in the actual frequency of the clocksource to be made incorrect. I believe this difference would affect all clocksources, although to differing degrees depending on the clocksource resolution. The issue was introduced when my HZ free ntp patch landed in 2.6.21-rc1, so my apologies for the mistake, and for not noticing it until now. The following patch, corrects the clocksource's initialization code so it uses the same interval length as the code in ntp.c. After applying this patch, the drift value for the same system went from ~283ppm to only 2.635ppm. I believe this patch to be good, however it does affect all arches and I've only tested on x86, so some caution is advised. I do think it would be a likely candidate for a stable 2.6.24.x release. Any thoughts or feedback would be appreciated. Signed-off-by: John Stultz Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/time/timekeeping.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel/time/timekeeping.c') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 77680195cf84..092a2366b5a9 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -186,7 +186,8 @@ static void change_clocksource(void) clock->error = 0; clock->xtime_nsec = 0; - clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); + clocksource_calculate_interval(clock, + (unsigned long)(current_tick_length()>>TICK_LENGTH_SHIFT)); tick_clock_notify(); @@ -243,7 +244,8 @@ void __init timekeeping_init(void) ntp_clear(); clock = clocksource_get_next(); - clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); + clocksource_calculate_interval(clock, + (unsigned long)(current_tick_length()>>TICK_LENGTH_SHIFT)); clock->cycle_last = clocksource_read(clock); xtime.tv_sec = sec; -- cgit v1.2.3