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Diffstat (limited to 'arch')
-rw-r--r--arch/x86_64/kernel/time.c63
1 files changed, 35 insertions, 28 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index ab9bea82945f..51afb07bc14e 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -56,6 +56,13 @@ DEFINE_SPINLOCK(i8253_lock);
int nohpet __initdata = 0;
static int notsc __initdata = 0;
+#define USEC_PER_TICK (USEC_PER_SEC / HZ)
+#define NSEC_PER_TICK (NSEC_PER_SEC / HZ)
+#define FSEC_PER_TICK (FSEC_PER_SEC / HZ)
+
+#define NS_SCALE 10 /* 2^10, carefully chosen */
+#define US_SCALE 32 /* 2^32, arbitralrily chosen */
+
unsigned int cpu_khz; /* TSC clocks / usec, not used here */
static unsigned long hpet_period; /* fsecs / HPET clock */
unsigned long hpet_tick; /* HPET clocks / interrupt */
@@ -88,7 +95,7 @@ static inline unsigned int do_gettimeoffset_tsc(void)
t = get_cycles_sync();
if (t < vxtime.last_tsc)
t = vxtime.last_tsc; /* hack */
- x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> 32;
+ x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> US_SCALE;
return x;
}
@@ -96,7 +103,7 @@ static inline unsigned int do_gettimeoffset_hpet(void)
{
/* cap counter read to one tick to avoid inconsistencies */
unsigned long counter = hpet_readl(HPET_COUNTER) - vxtime.last;
- return (min(counter,hpet_tick) * vxtime.quot) >> 32;
+ return (min(counter,hpet_tick) * vxtime.quot) >> US_SCALE;
}
unsigned int (*do_gettimeoffset)(void) = do_gettimeoffset_tsc;
@@ -116,7 +123,7 @@ void do_gettimeofday(struct timeval *tv)
seq = read_seqbegin(&xtime_lock);
sec = xtime.tv_sec;
- usec = xtime.tv_nsec / 1000;
+ usec = xtime.tv_nsec / NSEC_PER_USEC;
/* i386 does some correction here to keep the clock
monotonous even when ntpd is fixing drift.
@@ -127,14 +134,14 @@ void do_gettimeofday(struct timeval *tv)
in arch/x86_64/kernel/vsyscall.c and export all needed
variables in vmlinux.lds. -AK */
- t = (jiffies - wall_jiffies) * (1000000L / HZ) +
+ t = (jiffies - wall_jiffies) * USEC_PER_TICK +
do_gettimeoffset();
usec += t;
} while (read_seqretry(&xtime_lock, seq));
- tv->tv_sec = sec + usec / 1000000;
- tv->tv_usec = usec % 1000000;
+ tv->tv_sec = sec + usec / USEC_PER_SEC;
+ tv->tv_usec = usec % USEC_PER_SEC;
}
EXPORT_SYMBOL(do_gettimeofday);
@@ -155,8 +162,8 @@ int do_settimeofday(struct timespec *tv)
write_seqlock_irq(&xtime_lock);
- nsec -= do_gettimeoffset() * 1000 +
- (jiffies - wall_jiffies) * (NSEC_PER_SEC/HZ);
+ nsec -= do_gettimeoffset() * NSEC_PER_USEC +
+ (jiffies - wall_jiffies) * NSEC_PER_TICK;
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
@@ -286,7 +293,7 @@ unsigned long long monotonic_clock(void)
this_offset = hpet_readl(HPET_COUNTER);
} while (read_seqretry(&xtime_lock, seq));
offset = (this_offset - last_offset);
- offset *= (NSEC_PER_SEC/HZ) / hpet_tick;
+ offset *= NSEC_PER_TICK / hpet_tick;
} else {
do {
seq = read_seqbegin(&xtime_lock);
@@ -295,7 +302,8 @@ unsigned long long monotonic_clock(void)
base = monotonic_base;
} while (read_seqretry(&xtime_lock, seq));
this_offset = get_cycles_sync();
- offset = (this_offset - last_offset)*1000 / cpu_khz;
+ /* FIXME: 1000 or 1000000? */
+ offset = (this_offset - last_offset)*1000 / cpu_khz;
}
return base + offset;
}
@@ -380,7 +388,7 @@ void main_timer_handler(struct pt_regs *regs)
}
monotonic_base +=
- (offset - vxtime.last)*(NSEC_PER_SEC/HZ) / hpet_tick;
+ (offset - vxtime.last) * NSEC_PER_TICK / hpet_tick;
vxtime.last = offset;
#ifdef CONFIG_X86_PM_TIMER
@@ -389,24 +397,25 @@ void main_timer_handler(struct pt_regs *regs)
#endif
} else {
offset = (((tsc - vxtime.last_tsc) *
- vxtime.tsc_quot) >> 32) - (USEC_PER_SEC / HZ);
+ vxtime.tsc_quot) >> US_SCALE) - USEC_PER_TICK;
if (offset < 0)
offset = 0;
- if (offset > (USEC_PER_SEC / HZ)) {
- lost = offset / (USEC_PER_SEC / HZ);
- offset %= (USEC_PER_SEC / HZ);
+ if (offset > USEC_PER_TICK) {
+ lost = offset / USEC_PER_TICK;
+ offset %= USEC_PER_TICK;
}
- monotonic_base += (tsc - vxtime.last_tsc)*1000000/cpu_khz ;
+ /* FIXME: 1000 or 1000000? */
+ monotonic_base += (tsc - vxtime.last_tsc) * 1000000 / cpu_khz;
vxtime.last_tsc = tsc - vxtime.quot * delay / vxtime.tsc_quot;
if ((((tsc - vxtime.last_tsc) *
- vxtime.tsc_quot) >> 32) < offset)
+ vxtime.tsc_quot) >> US_SCALE) < offset)
vxtime.last_tsc = tsc -
- (((long) offset << 32) / vxtime.tsc_quot) - 1;
+ (((long) offset << US_SCALE) / vxtime.tsc_quot) - 1;
}
if (lost > 0) {
@@ -466,16 +475,15 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
}
static unsigned int cyc2ns_scale __read_mostly;
-#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
static inline void set_cyc2ns_scale(unsigned long cpu_khz)
{
- cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
+ cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / cpu_khz;
}
static inline unsigned long long cycles_2_ns(unsigned long long cyc)
{
- return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
+ return (cyc * cyc2ns_scale) >> NS_SCALE;
}
unsigned long long sched_clock(void)
@@ -488,7 +496,7 @@ unsigned long long sched_clock(void)
Disadvantage is a small drift between CPUs in some configurations,
but that should be tolerable. */
if (__vxtime.mode == VXTIME_HPET)
- return (hpet_readl(HPET_COUNTER) * vxtime.quot) >> 32;
+ return (hpet_readl(HPET_COUNTER) * vxtime.quot) >> US_SCALE;
#endif
/* Could do CPU core sync here. Opteron can execute rdtsc speculatively,
@@ -631,7 +639,7 @@ static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
if (!(freq->flags & CPUFREQ_CONST_LOOPS))
- vxtime.tsc_quot = (1000L << 32) / cpu_khz;
+ vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
}
set_cyc2ns_scale(cpu_khz_ref);
@@ -823,8 +831,7 @@ static int hpet_init(void)
if (hpet_period < 100000 || hpet_period > 100000000)
return -1;
- hpet_tick = (1000000000L * (USEC_PER_SEC / HZ) + hpet_period / 2) /
- hpet_period;
+ hpet_tick = (FSEC_PER_TICK + hpet_period / 2) / hpet_period;
hpet_use_timer = (id & HPET_ID_LEGSUP);
@@ -898,7 +905,7 @@ void __init time_init(void)
-xtime.tv_sec, -xtime.tv_nsec);
if (!hpet_init())
- vxtime_hz = (1000000000000000L + hpet_period / 2) / hpet_period;
+ vxtime_hz = (FSEC_PER_SEC + hpet_period / 2) / hpet_period;
else
vxtime.hpet_address = 0;
@@ -927,8 +934,8 @@ void __init time_init(void)
vxtime_hz / 1000000, vxtime_hz % 1000000, timename, gtod);
printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n",
cpu_khz / 1000, cpu_khz % 1000);
- vxtime.quot = (1000000L << 32) / vxtime_hz;
- vxtime.tsc_quot = (1000L << 32) / cpu_khz;
+ vxtime.quot = (USEC_PER_SEC << US_SCALE) / vxtime_hz;
+ vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
vxtime.last_tsc = get_cycles_sync();
setup_irq(0, &irq0);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-30 07:06:31 +0000