diff options
| -rw-r--r-- | kernel/timer.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/timer.c b/kernel/timer.c index 3ba10fa..6a2e5f8 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -752,6 +752,15 @@ static void second_overflow(void) else time_adj += (time_adj >> 2) + (time_adj >> 5); #endif +#if HZ == 250 + /* Compensate for (HZ==250) != (1 << SHIFT_HZ). + * Add 1.5625% and 0.78125% to get 255.85938; => only 0.05% error (p. 14) + */ + if (time_adj < 0) + time_adj -= (-time_adj >> 6) + (-time_adj >> 7); + else + time_adj += (time_adj >> 6) + (time_adj >> 7); +#endif #if HZ == 1000 /* Compensate for (HZ==1000) != (1 << SHIFT_HZ). * Add 1.5625% and 0.78125% to get 1023.4375; => only 0.05% error (p. 14) |
