diff options
Diffstat (limited to 'kernel/timer.c')
| -rw-r--r-- | kernel/timer.c | 47 |
1 files changed, 28 insertions, 19 deletions
diff --git a/kernel/timer.c b/kernel/timer.c index 623f9ea198d8..6811436a031d 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -597,7 +597,6 @@ long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */ long time_precision = 1; /* clock precision (us) */ long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */ long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */ -static long time_phase; /* phase offset (scaled us) */ long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC; /* frequency offset (scaled ppm)*/ static long time_adj; /* tick adjust (scaled 1 / HZ) */ @@ -747,27 +746,14 @@ static long adjtime_adjustment(void) } /* in the NTP reference this is called "hardclock()" */ -static void update_wall_time_one_tick(void) +static void update_ntp_one_tick(void) { - long time_adjust_step, delta_nsec; + long time_adjust_step; time_adjust_step = adjtime_adjustment(); if (time_adjust_step) /* Reduce by this step the amount of time left */ time_adjust -= time_adjust_step; - delta_nsec = tick_nsec + time_adjust_step * 1000; - /* - * Advance the phase, once it gets to one microsecond, then - * advance the tick more. - */ - time_phase += time_adj; - if ((time_phase >= FINENSEC) || (time_phase <= -FINENSEC)) { - long ltemp = shift_right(time_phase, (SHIFT_SCALE - 10)); - time_phase -= ltemp << (SHIFT_SCALE - 10); - delta_nsec += ltemp; - } - xtime.tv_nsec += delta_nsec; - time_interpolator_update(delta_nsec); /* Changes by adjtime() do not take effect till next tick. */ if (time_next_adjust != 0) { @@ -872,8 +858,13 @@ device_initcall(timekeeping_init_device); */ static void update_wall_time(void) { + static s64 remainder_snsecs, error; + s64 snsecs_per_sec; cycle_t now, offset; + snsecs_per_sec = (s64)NSEC_PER_SEC << clock->shift; + remainder_snsecs += (s64)xtime.tv_nsec << clock->shift; + now = read_clocksource(clock); offset = (now - last_clock_cycle)&clock->mask; @@ -881,17 +872,35 @@ static void update_wall_time(void) * case of lost or late ticks, it will accumulate correctly. */ while (offset > clock->interval_cycles) { + /* get the ntp interval in clock shifted nanoseconds */ + s64 ntp_snsecs = current_tick_length(clock->shift); + /* accumulate one interval */ + remainder_snsecs += clock->interval_snsecs; last_clock_cycle += clock->interval_cycles; offset -= clock->interval_cycles; - update_wall_time_one_tick(); - if (xtime.tv_nsec >= 1000000000) { - xtime.tv_nsec -= 1000000000; + /* interpolator bits */ + time_interpolator_update(clock->interval_snsecs + >> clock->shift); + /* increment the NTP state machine */ + update_ntp_one_tick(); + + /* accumulate error between NTP and clock interval */ + error += (ntp_snsecs - (s64)clock->interval_snsecs); + + /* correct the clock when NTP error is too big */ + remainder_snsecs += make_ntp_adj(clock, offset, &error); + + if (remainder_snsecs >= snsecs_per_sec) { + remainder_snsecs -= snsecs_per_sec; xtime.tv_sec++; second_overflow(); } } + /* store full nanoseconds into xtime */ + xtime.tv_nsec = remainder_snsecs >> clock->shift; + remainder_snsecs -= (s64)xtime.tv_nsec << clock->shift; } /* |