diff options
| -rw-r--r-- | include/linux/jiffies.h | 21 | ||||
| -rw-r--r-- | include/linux/timex.h | 2 | ||||
| -rw-r--r-- | kernel/time/jiffies.c | 2 | ||||
| -rw-r--r-- | kernel/time/ntp.c | 2 |
4 files changed, 16 insertions, 11 deletions
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h index 7d24466fb80..82680541576 100644 --- a/include/linux/jiffies.h +++ b/include/linux/jiffies.h @@ -55,21 +55,26 @@ /* LATCH is used in the interval timer and ftape setup. */ # define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */ -/* HZ is the requested value. ACTHZ is actual HZ ("<< 8" is for accuracy) */ -# define ACTHZ (SH_DIV(CLOCK_TICK_RATE, LATCH, 8)) +/* + * HZ is the requested value. However the CLOCK_TICK_RATE may not allow + * for exactly HZ. So SHIFTED_HZ is high res HZ ("<< 8" is for accuracy) + */ +# define SHIFTED_HZ (SH_DIV(CLOCK_TICK_RATE, LATCH, 8)) #else -# define ACTHZ (HZ << 8) +# define SHIFTED_HZ (HZ << 8) #endif -/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */ -#define TICK_NSEC (SH_DIV (1000000UL * 1000, ACTHZ, 8)) +/* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */ +#define TICK_NSEC (SH_DIV(1000000UL * 1000, SHIFTED_HZ, 8)) /* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ #define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) -/* TICK_USEC_TO_NSEC is the time between ticks in nsec assuming real ACTHZ and */ -/* a value TUSEC for TICK_USEC (can be set bij adjtimex) */ -#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV (TUSEC * USER_HZ * 1000, ACTHZ, 8)) +/* + * TICK_USEC_TO_NSEC is the time between ticks in nsec assuming SHIFTED_HZ and + * a value TUSEC for TICK_USEC (can be set bij adjtimex) + */ +#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV(TUSEC * USER_HZ * 1000, SHIFTED_HZ, 8)) /* some arch's have a small-data section that can be accessed register-relative * but that can only take up to, say, 4-byte variables. jiffies being part of diff --git a/include/linux/timex.h b/include/linux/timex.h index 99bc88b1fc0..7c5ceb20e03 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -232,7 +232,7 @@ struct timex { * estimated error = NTP dispersion. */ extern unsigned long tick_usec; /* USER_HZ period (usec) */ -extern unsigned long tick_nsec; /* ACTHZ period (nsec) */ +extern unsigned long tick_nsec; /* SHIFTED_HZ period (nsec) */ extern void ntp_init(void); extern void ntp_clear(void); diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c index a470154e040..46da0537c10 100644 --- a/kernel/time/jiffies.c +++ b/kernel/time/jiffies.c @@ -37,7 +37,7 @@ * requested HZ value. It is also not recommended * for "tick-less" systems. */ -#define NSEC_PER_JIFFY ((u32)((((u64)NSEC_PER_SEC)<<8)/ACTHZ)) +#define NSEC_PER_JIFFY ((u32)((((u64)NSEC_PER_SEC)<<8)/SHIFTED_HZ)) /* Since jiffies uses a simple NSEC_PER_JIFFY multiplier * conversion, the .shift value could be zero. However diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index b7fbadc5c97..24174b4d669 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -28,7 +28,7 @@ DEFINE_SPINLOCK(ntp_lock); /* USER_HZ period (usecs): */ unsigned long tick_usec = TICK_USEC; -/* ACTHZ period (nsecs): */ +/* SHIFTED_HZ period (nsecs): */ unsigned long tick_nsec; static u64 tick_length; |