From 4221133845f81ab4428c79a89e37be2c87624c1a Mon Sep 17 00:00:00 2001 From: Vojtech Pavlik Date: Mon, 26 Jun 2006 13:58:32 +0200 Subject: [PATCH] [PATCH] x86_64: Make use of the *PER* constants in time.c This patch makes use of the newly added conversion constants in time.h to x86-64 time.c. The code gets significantly easier to understand. Signed-off-by: Vojtech Pavlik Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/time.c | 63 ++++++++++++++++++++++----------------- 1 file 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); -- 2.20.1