Roman, All,
Here is the second of two patches which try a minimized version of my
ntp rework patches.
This patch further changes the interrupt time NTP code, breaking out the
leapsecond processing and introduces an accessor to a shifted ppm
adjustment value.
Again, this patch should not affect the existing behavior, but just
separate the logical functionality so it can be re-used by my timeofday
patches.
thanks
-john
linux-2.6.14-rc2_timeofday-ntp-part2_B6test.patch
============================================
diff --git a/kernel/timer.c b/kernel/timer.c
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -620,6 +620,78 @@ static long time_adj; /* tick adjust (
long time_reftime; /* time at last adjustment (s) */
long time_adjust;
long time_next_adjust;
+long time_adjust_step; /* per tick time_adjust step */
+
+long total_sppm; /* shifted ppm sum of all NTP adjustments */
+long offset_adj_ppm;
+long tick_adj_ppm;
+long singleshot_adj_ppm;
+
+#define MAX_SINGLESHOT_ADJ 500 /* (ppm) */
+#define SEC_PER_DAY 86400
+
+/**
+ * ntp_leapsecond - NTP leapsecond processing code.
+ * now: the current time
+ *
+ * Returns the number of seconds (-1, 0, or 1) that
+ * should be added to the current time to properly
+ * adjust for leapseconds.
+ */
+int ntp_leapsecond(struct timespec now)
+{
+ /*
+ * Leap second processing. If in leap-insert state at
+ * the end of the day, the system clock is set back one
+ * second; if in leap-delete state, the system clock is
+ * set ahead one second.
+ */
+ static time_t leaptime = 0;
+
+ switch (time_state) {
+
+ case TIME_OK:
+ if (time_status & STA_INS)
+ time_state = TIME_INS;
+ else if (time_status & STA_DEL)
+ time_state = TIME_DEL;
+
+ /* calculate end of today (23:59:59)*/
+ leaptime = now.tv_sec + SEC_PER_DAY -
+ (now.tv_sec % SEC_PER_DAY) - 1;
+ break;
+
+ case TIME_INS:
+ /* Once we are at (or past) leaptime, insert the second */
+ if (now.tv_sec >= leaptime) {
+ time_state = TIME_OOP;
+ printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n");
+ return -1;
+ }
+ break;
+
+ case TIME_DEL:
+ /* Once we are at (or past) leaptime, delete the second */
+ if (now.tv_sec >= leaptime) {
+ time_state = TIME_WAIT;
+ printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n");
+ return 1;
+ }
+ break;
+
+ case TIME_OOP:
+ /* Wait for the end of the leap second*/
+ if (now.tv_sec > (leaptime + 1))
+ time_state = TIME_WAIT;
+ time_state = TIME_WAIT;
+ break;
+
+ case TIME_WAIT:
+ if (!(time_status & (STA_INS | STA_DEL)))
+ time_state = TIME_OK;
+ }
+ return 0;
+}
/*
* this routine handles the overflow of the microsecond field
@@ -642,59 +714,6 @@ static void second_overflow(void)
}
/*
- * Leap second processing. If in leap-insert state at
- * the end of the day, the system clock is set back one
- * second; if in leap-delete state, the system clock is
- * set ahead one second. The microtime() routine or
- * external clock driver will insure that reported time
- * is always monotonic. The ugly divides should be
- * replaced.
- */
- switch (time_state) {
-
- case TIME_OK:
- if (time_status & STA_INS)
- time_state = TIME_INS;
- else if (time_status & STA_DEL)
- time_state = TIME_DEL;
- break;
-
- case TIME_INS:
- if (xtime.tv_sec % 86400 == 0) {
- xtime.tv_sec--;
- wall_to_monotonic.tv_sec++;
- /* The timer interpolator will make time change gradually instead
- * of an immediate jump by one second.
- */
- time_interpolator_update(-NSEC_PER_SEC);
- time_state = TIME_OOP;
- clock_was_set();
- printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n");
- }
- break;
-
- case TIME_DEL:
- if ((xtime.tv_sec + 1) % 86400 == 0) {
- xtime.tv_sec++;
- wall_to_monotonic.tv_sec--;
- /* Use of time interpolator for a gradual change of time */
- time_interpolator_update(NSEC_PER_SEC);
- time_state = TIME_WAIT;
- clock_was_set();
- printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n");
- }
- break;
-
- case TIME_OOP:
- time_state = TIME_WAIT;
- break;
-
- case TIME_WAIT:
- if (!(time_status & (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- }
-
- /*
* Compute the phase adjustment for the next second. In
* PLL mode, the offset is reduced by a fixed factor
* times the time constant. In FLL mode the offset is
@@ -711,6 +730,13 @@ static void second_overflow(void)
time_offset -= ltemp;
time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+ offset_adj_ppm = shift_right(ltemp, SHIFT_UPDATE); /* ppm */
+
+ /* first calculate usec/user_tick offset */
+ tick_adj_ppm = ((USEC_PER_SEC + USER_HZ/2)/USER_HZ) - tick_usec;
+ /* multiply by user_hz to get usec/sec => ppm */
+ tick_adj_ppm *= USER_HZ;
+
/*
* Compute the frequency estimate and additional phase
* adjustment due to frequency error for the next
@@ -742,9 +768,17 @@ static void second_overflow(void)
#endif
}
-long time_adjust_step;
-static void ntp_advance(unsigned long interval_ns)
+/**
+ * ntp_get_ppm_adjustment - Returns Shifted PPM adjustment
+ *
+ */
+long ntp_get_ppm_adjustment(void)
+{
+ return total_sppm;
+}
+
+void ntp_advance(unsigned long interval_ns)
{
static unsigned long interval_sum;
@@ -772,6 +806,7 @@ static void ntp_advance(unsigned long in
}
interval_ns -= tick_nsec;
}
+ singleshot_adj_ppm = time_adjust_step*(1000000/HZ); /* usec/tick => ppm */
/* Changes by adjtime() do not take effect till next tick. */
if (time_next_adjust) {
@@ -783,6 +818,12 @@ static void ntp_advance(unsigned long in
interval_sum -= NSEC_PER_SEC;
second_overflow();
}
+
+ /* calculate the total continuous ppm adjustment */
+ total_sppm = time_freq; /* already shifted by SHIFT_USEC */
+ total_sppm += offset_adj_ppm << SHIFT_USEC;
+ total_sppm += tick_adj_ppm << SHIFT_USEC;
+ total_sppm += singleshot_adj_ppm << SHIFT_USEC;
}
/*
@@ -817,8 +858,18 @@ static void update_wall_time(unsigned lo
xtime.tv_nsec += delta_nsec;
if (xtime.tv_nsec >= 1000000000) {
+ int leapsecond;
xtime.tv_nsec -= 1000000000;
xtime.tv_sec++;
+ /* process leapsecond */
+ leapsecond = ntp_leapsecond(xtime);
+ if (leapsecond) {
+ xtime.tv_sec += leapsecond;
+ wall_to_monotonic.tv_sec -= leapsecond;
+ /* Use of time interpolator for a gradual change of time */
+ time_interpolator_update(leapsecond*NSEC_PER_SEC);
+ clock_was_set();
+ }
}
ntp_advance(tick_nsec);
time_interpolator_update(delta_nsec);
-
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