The patch titled
ntp: correct inconsistent interval/tick_length usage
has been removed from the -mm tree. Its filename was
correct-inconsistent-ntp-interval-tick_length-usage.patch
This patch was dropped because an updated version will be merged
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ntp: correct inconsistent interval/tick_length usage
From: john stultz <johnstul@xxxxxxxxxx>
Correct NTP drift caused by using inconsistent NTP_INTERVAL_LENGTHs in
clocksource initialization and error accumulation. This corrects a 280ppm
drift seen on some systems using acpi_pm, and affects other clocksources as
well (likely to a lesser degree).
Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
Cc: Roman Zippel <zippel@xxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/timex.h | 8 +++++++-
kernel/time/ntp.c | 4 ----
2 files changed, 7 insertions(+), 5 deletions(-)
diff -puN include/linux/timex.h~correct-inconsistent-ntp-interval-tick_length-usage include/linux/timex.h
--- a/include/linux/timex.h~correct-inconsistent-ntp-interval-tick_length-usage
+++ a/include/linux/timex.h
@@ -232,7 +232,13 @@ static inline int ntp_synced(void)
#else
#define NTP_INTERVAL_FREQ (HZ)
#endif
-#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
+
+#define CLOCK_TICK_OVERFLOW (LATCH * HZ - CLOCK_TICK_RATE)
+#define CLOCK_TICK_ADJUST (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
+ (s64)CLOCK_TICK_RATE)
+
+/* Because using NSEC_PER_SEC would be too easy */
+#define NTP_INTERVAL_LENGTH ((((s64)TICK_USEC*NSEC_PER_USEC*USER_HZ)+CLOCK_TICK_ADJUST)/NTP_INTERVAL_FREQ)
/* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
extern u64 current_tick_length(void);
diff -puN kernel/time/ntp.c~correct-inconsistent-ntp-interval-tick_length-usage kernel/time/ntp.c
--- a/kernel/time/ntp.c~correct-inconsistent-ntp-interval-tick_length-usage
+++ a/kernel/time/ntp.c
@@ -43,10 +43,6 @@ long time_freq; /* frequency offset (
static long time_reftime; /* time at last adjustment (s) */
long time_adjust;
-#define CLOCK_TICK_OVERFLOW (LATCH * HZ - CLOCK_TICK_RATE)
-#define CLOCK_TICK_ADJUST (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
- (s64)CLOCK_TICK_RATE)
-
static void ntp_update_frequency(void)
{
u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
_
Patches currently in -mm which might be from johnstul@xxxxxxxxxx are
git-x86.patch
time-fix-sysfs_show_availablecurrent_clocksources-buffer-overflow-problem.patch
add-hpet-rtc-emulation-to-rtc_drv_cmos.patch
clocksource-remove-redundant-code.patch
clockevent-simplify-list-operations.patch
timekeeping-rename-timekeeping_is_continuous-to-timekeeping_valid_for_hres.patch
time-fix-typo-in-comments.patch
time-delete-comments-that-refer-to-noexistent-symbols.patch
correct-inconsistent-ntp-interval-tick_length-usage.patch
-
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