Deprecated: The each() function is deprecated. This message will be suppressed on further calls in /home/zhenxiangba/zhenxiangba.com/public_html/phproxy-improved-master/index.php on line 456
$B;~9o$H;~4V$N4IM}(B

$B;~9o$H;~4V$N4IM}(B

$B>pJs3XN`(B $B%*%Z%l!<%F%#%s%0%7%9%F%`#I#I(B					2007$BG/(B01$B7n(B23$BF|(B

                                       $BC^GHBg3X%7%9%F%`>pJs9)3X8&5f2J(B
				       $B%3%s%T%e!<%?%5%$%(%s%9@l96(B, $BEE;R!&>pJs9)3X7O(B
                                       $B?7>k(B $BLw(B
                                       <yas@is.tsukuba.ac.jp>

$B$3$N%Z!<%8$O!" http://www.coins.tsukuba.ac.jp/~yas/coins/os2-2006/2007-01-23
$B$"$k$$$O!" http://www.coins.tsukuba.ac.jp/~yas/
http://www.cs.tsukuba.ac.jp/~yas/

$B"#I|=,(B

$B%7%9%F%`%W%m%0%i%`(B
- gettimeofday(), time(), struct timeval, time_t t
- asctime(), ctime(), gmtime(), localtime(), mktime(), struct tm
- SIGALRM, SIGALRM, SIGPROF, setitimer()

$B"#;29MJ88%(B

VMware: "Timekeeping in VMware Virtual Machines", White paper (2005).

$B9b669@OB(B, $B>.ED0oO:(B, $B;3H(0Y:45W(B: "Linux$B%+!<%M%k(B2.6$B2rFI<<(B",$B%U%H%P%s%/%/%j%(%$%F%#%V(B (2006/11/18). ISBN-13: 978-4797338263.

Marshall Kirk McKusick, George V. Neville$B!>(BNeil ($BCx(B), $B2NBe(B $BOB@5(B, $B:=86(B $B=(\2r(B", $B%"%9%-!<(B (2005/10/18). ISBN-13: 978-4756146793. Marshall Kirk McKusick, George V. Neville-Neil: "The Design And Implementation Of The Freebsd Operating System Addison-Wesley (2004/7/30). ISBN-13: 978-0201702453

$B"#%*%Z%l!<%F%#%s%0!&%7%9%F%`(B

$B#2$D$N%$%s%?%U%'!<%9$r!"$&$^$/$D$J$0$b$N!#(B

$B?^(B? $B%*%Z%l!<%F%#%s%0!&%7%9%F%`$NF/$-(B

$B$I$s$J%7%9%F%`!&%3!<%k$rDs6!$9$Y$-$+(B
$B$I$s$J%O!<%I%&%'%"$,MxMQ$G$-$k$N$+(B
($BFbIt$GI,MW$H$5$l$k5!G=(B)

$B%i%$%V%i%j$H%7%9%F%`!&%3!<%k$N0c$$$KCm0U(B

$B"#;~9o$H;~4V(B

$B"!I,MW$J5!G=(B

$B%+%l%s%@;~9o$NDs6!(B, gettimeofday(), time()
$B%$%s%?!<%P%k%?%$%^(B, setitimer()
$B;~4V@Z$l(B, select(), poll()
$B%+!<%M%kFb$N;E;v!#;~4V9o$_(B(time slice)$B$N
$B"!%+%l%s%@;~9o$NDs6!(B
```
struct timeval {
	long    tv_sec;         /* seconds since Jan. 1, 1970 */
	long    tv_usec;        /* and microseconds */
};

int gettimeofday(struct timeval *tp, struct timezone *tzp)

struct timeval  tv;
gettimeofday(&tv, NULL);
```
$B&L(B($B%^%$%/%m(B)$BICC10L$N;~9o$rJV$9!#(BPOSIX 1003.1, 2003 $B$G$O!"%J%NICC10L!#(B
```
struct timespec  {
    time_t tv_sec;            /* Seconds.  */
    long int tv_nsec;         /* Nanoseconds.  */
};

int clock_settime(clockid_t clock_id, const struct timespec *tp);
int clock_gettime(clockid_t clock_id, struct timespec *tp);
int clock_getres(clockid_t clock_id, struct timespec *res);
```
$B"!%$%s%?!<%P%k%?%$%^(B
$BDj4|E*$J;E;v$r$7$?$$;~$K;H$&(B
```
struct itimerval {
    struct timeval it_interval; /* next value */
    struct timeval it_value;    /* current value */
};

int setitimer(int which, const struct itimerval *value, struct itimerval *ovalue);
```
- $B$^$:!"(Bit_value $B$G;XDj$5$l$?;~4V$,7P$D$H!"%7%0%J%k$,DLCN$5$l$k!#(B
- $B0J8e!"(Bit_interval $BKh$K%7%0%J%k$,DLCN$5$l$k!#(B
$BF1$8OC!#(B
1. $BFbIt$K%+%&%s%H%@%&%s$7$F$$$/JQ?t$,$"$k!#(B
2. $B=i4|CM$H$7$F!"(Bit_value $B$r@_Dj$9$k!#(B
3. $BJQ?t$,(B 0 $B$K$J$k$H!"%7%0%J%k$,DLCN$5$l$k!#(B
4. $BJQ?t$NCM$r!"(Bit_interval $B$K@_Dj$9$k!#(B
5. 3. $B$r!"2r=|$5$l$k$^$G7+$jJV$9!#(B
$B"!;~4V@Z$l(B
```
int  select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
     		struct timeval *timeout);
int  poll(struct pollfd *fds, nfds_t nfds, int timeout);
```
$B%M%C%H%o!<%/!&%W%m%0%i%`$G$h$/;H$&!#J#?t$NF~NO$r4F;k$9$k!#;XDj$5$l$?;~(B $B4V!"F~NO$,$J$1$l$P!"%7%9%F%`!&%3!<%k$+$iI|5"$9$k!#(B
$B$J$K$b$7$J$$;~4V@Z$l!#(B
```
unsigned int sleep(unsigned int seconds);
int usleep(useconds_t usec)
int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
```
$B"!%7%0%J%k$H%O!<%I%&%'%"3d9~$_(B
Unix $B$N%7%0%J%k$O!"%O!<%I%&%'%"3d9~$_$r85$K5!G=$,@_7W$5$l$F$$$k!#(B
- $B.?t!"8GDjE*$JMxMQ(B
- $B0z?t$,$J$$(B
- $B%W%m%;%9A4BN$GBg0hE*!J%9%l%C%I$K3d9~$_$O9g$o$J$$!K(B
- $B3d9~$_6X;_(B($B3d9~$_%^%9%/(B)$B$H$$$&9M$(J}$,$"$k(B
up-call $B$NJ}$,!"%=%U%H%&%'%"$H$7$F$O;H$$$d$9$$!#(B
$B"!(Bup-call

$B?^(B? $B%7%9%F%`%3!<%k$H%"%C%W%3!<%k(B
$B%"%C%W%3!<%k$O!"%7%9%F%`!&%3!<%k$N5U$K!"%*%Z%l!<%F%#%s%0!&%7%9%F%`$,%f!<(B $B%6!&%l%Y%k$N4X?t$r8F$S=P$9!#(B $B%&%$%s%I%&!&%7%9%F%`$N%W%m%0%i%`$G$O!"(Bcall-back $B4X?t$d(Blistener $B$H$7$FMx(B $BMQ$5$l$F$$$k!#(B
$B"#;~9o!&;~4V4XO"$N%O!<%I%&%'%"(B
$B%3%s%T%e!<%?$K$h$C$F0c$&!#$3$3$G$O!"(BPC/AT $B$NOC!#(B
$B"!4pK\E*$J%b%G%k(B
$B%O!<%I%&%'%"$O!"4JC1!#H/?64o$H%+%&%s%H%@%&%s$9$k%+%&%s%?$r;H$&!#(B

$B?^(B? $B%?%$%^4XO"$N%O!<%I%&%'%"$N4pK\%b%G%k(B
- $BH/?64o$O!"0lDj$N<~GH?t$G%+%&%s%?$K?.9f$rAw$k!#(B
- $BH/?64o$N<~GH?t$O!"%=%U%H%&%'%"$G@_Dj2DG=$J>l9g$,$"$k!#(B
- $B%+%&%s%?$O!"%=%U%H%&%'%"$GFI$_=q$-$G$-$k!#(B
- $B%+%&%s%?$O!"#0$K$J$C$?$i!"?.9f$r@8@.$9$k!#$=$l$K$h$j!"(B CPU $B$K3d9~$_$,$+$+$k!#(B
- $B%+%&%s%?$N%b!<%I$,0l2s@Z$j(B(one shot mode)$B$J$i!"$3$l$G=*$o$j!#(B
- $B%+%&%s%?$N%b!<%I$,Dj4|E*(B(periodic mode)$B$J$i!"JL$N%l%8%9%?$+$iCM$r(B $B:F@_Dj$9$k!#(B
$B%+%&%s%H%@%&%s$G$O$J$/%+%&%s%H%"%C%W$9$k$b$N$b$"$k!#(B
$B"!(BPIT (Programmable Interval Timer)
$B8E$$%?%$%^!&%G%P%$%9!#(B
- $BH/?64o$N<~GH?t$O!"(B 1193182Hz$B!#(B NTSC $B?.9f$N(B 1/3$B!#Ev;~!" $B%+%&%s%?!":F@_DjMQ$N%l%8%9%?$O!"(B16$B%S%C%H!#(B
- PIT $B%G%P%$%9$O!"(B3 $B$D$N%?%$%^$r;}$D!#(B
  - 0: $B3d9~$_@8@.2DG=!#(BOS$B$N;~4V4IM}$KE,$9$k!#(B
  - 1: Dynamic RAM $B$N%j%U%l%C%7%e!#(B
  - 2: $B%9%T!<%+!<$N%H!<%s@8@.(B
Linux $B$O!"(B0 $BHV$r
$B"!(BCMOS RTC (Real Time Clock) $BEE8;%*%U;~$K$b!"%P%C%F%j$GF0:n$7$F$$$k!#(BBIOS $BMQ$N@_Dj$rJ];}$9$k%a%b%j$N(B $B0lIt!#(B $BEv;~!"(BCMOS $B$O!"!VDc>CHqEENO!WMQ$H$7$F$@$1;H$o$l$F$$$?!#(B $B:#$O!"IaDL!#(B $B!!(B
2$B$D$N5!G=$,$"$k!#(B

TOD clock
$B;~9o$r!"(Byear/month/day hour:minute:second $B$H$$$&7A<0$G;}$D!#(B $BIC0J2<$OFI$a$J$$!#(B
$BDj4|E*$J3d9~$_MQ(B
2Hz $B$+$i(B 8192Hz $B$NHO0O$G!"(B2 $B$NQQ>h$N<~4|$G3d9~$_$r5/$3$;$k!#(B
$B@)Ls(B
- $B%+%&%s%?$NCM$rFI$_=q$-$G$-$J$$(B
- $B=i4|CM$O!"(B2 $B$NQQ>h$7$+@_Dj$G$-$J$$!#(B
$B$=$NB>$N3d9~$_(B
- TOD $B%/%m%C%/$,99?7$5$l$?!#KhIC#12s!#(B
- $BL\3P$^$7!#(BTOD $B%/%m%C%/$,@_Dj$5$l$?;~9o$H0lCW$7$?;~!#(B
$B"!(BLocal APIC (Advanced Programmable Interrupt Controller) Timers
Local APIC $B$O!"3d9~$_$N%k!<%F%#%s%0$K;H$o$l$k!#(B $B%^%k%A%W%m%;%C%5$G$b!"(BCPU $BKh$KFHN)!#(B Pentium $B0J9_$G$O!"(BCPU $B$KFbB"!#(B
- $B%+%&%s%?$H=i4|CM$O(B 32 $B%S%C%H!#(B
- $BF~NO<~GH?t$O!"(BCPU $B$N%U%m%s%H%5%$%I!&%a%b%j!&%P%9$N<~GH?t$HF1$8!#(B (DDR $BMQ0JA0(B)
- PIT $B$d(B CMOS RTC $B$h$j9b@:EY$@$,!"%=%U%H%&%'%"$+$i<~GH?t$rD4$Y$kJ}K!$,$J$$!#(B (PIT $B$d(B CMOS RTC$B$r;H$C$FD4$Y$k$7$+$J$$!#(B)
$B"!(BACPI (Advanced Configuration and Power Interface)
$B%A%C%W%;%C%H!&%?%$%^$H$b8F$P$l$k!#(B
- $BH/?64o$O!"(B3579545 Hz (PIT $B$N(B 3 $BG\(B)
- $B%+%&%s%?$O!"(B24$B%S%C%H!#(B
- $B=i4|CM$rJ];}$9$k%l%8%9%?$,$J$$!#(B24 $B%S%C%H$G0l<~$9$k!#(B
- $B>e0L%S%C%H$,JQ2=$9$k$H3d9~$_$,$+$+$k!#(B
- $B>JEENO%b!<%I$G$b!"DL>oDL$jF0$-B3$1$k(B
Linux kernel 2.6 $B$O!"(BPIT $B$rJd@5$9$k$N$K;H$&!#(B
$B"!(BTSC (Time Stamp Counter)
Pentium $B0J9_$GMxMQ2DG=!#(B
- $BH/?64o$O!"(BCPU $B%/%m%C%/!#9b@:EY!#(B
- $B%+%&%s%?$O!"(B64 $B%S%C%H!#0l<~$9$k$N$K!"?tG/$+$+$k!#(B
- $B3d$j9~$_$r5/$3$95!G=$O$J$$!#(B
- $B=i4|CM$rJ];}$9$k%l%8%9%?$,$J$$(B
- $B%=%U%H%&%'%"$+$iFI$_=P$;$k!#(B(Pentium 4 $B$G$O!"CY$$!#(B)
- $B%f!<%6$+$i$b%"%/%;%92DG=$K$9$k$N$,IaDL!#(B
- $B%=%U%H%&%'%"$+$i<~GH?t$rD4$Y$kJ}K!$,$J$$!#(B (PIT $B$d(B CMOS RTC$B$r;H$C$FD4$Y$k$7$+$J$$!#(B)
- $B>JEENO$G(B CPU $B$N<~GH?t$rMn$9$3$H$,$"$k!#(B
- SMP $B$G$b!"(BCPU $B$OF1$8H/?64o$N=PNO$r;H$&$N$GF1$8$h$&$KA}$($k!#(BNUMA $B$G$OF0$+$J$$!#(B
Linux $B$N(B gettimeofday() $B$G!"(BPIT $B0J>e$N@:EY$r=P$9;~$K;H$&!#(B
$B"#(BLiux $B$K$*$1$k;~9o!&;~4V4IM}(B

$B"!(Bjiffies$BJQ?t(B
- $B%$%s%?!<%P%k!&%?%$%^$r;H$C$F!"(Bjiffies $B$H$$$&JQ?t$rA}$d$9!#(B $B#12s$N3d9~$_$r(B tick $B$H$$$&!#(B
- $BEAE}E*$J(B Unix $B$G$O!"(B1$BIC4V$K(B 100 $B2s(B-120 $B2s$N%?%$%^3d9~$_$r5/$3$9!#(B
- Linux $B$G$O!"(BHZ $B$H$$$&%3%s%Q%$%k;~$NDj?t$G@_Dj$5$l$k!#(B 100, 250, 1000 $B$J$I$K@_Dj$9$k$N$,IaDL!#(B
```
/* kernel/imer.c */
u64 jiffies_64;
void do_timer(unsigned long ticks)
{
        jiffies_64 += ticks;
        update_times(ticks);
}

/* include/asm-i386/mach-default/do_timer.h */
static inline void do_timer_interrupt_hook(void)
{
        do_timer(1);
...
}

/* arch/i386/kernel/time.c */
irqreturn_t timer_interrupt(int irq, void *dev_id) 
{
        do_timer_interrupt_hook();
}

/* arch/i386/mach-default/setup.c */

static struct irqaction irq0  = { timer_interrupt, IRQF_DISABLED, 
CPU_MASK_NONE, "timer", NULL, NULL};

void __init time_init_hook(void)
{
        setup_irq(0, &irq0);
}
```
$B"!(Bxtime$BJQ?t(B
xtime $B$O!"(B1970$BG/(B1$B7n(B1$BF|(B00:00:00(GMT)$B$+$i$NIC?t!#(Bgettimeofday() $B$GJV$5$l$kCM$r(B nano $BICC10L$GJ];}$7$F$$$k!#
/* kernel/time.c */ asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz) { if (likely(tv != NULL)) { struct timeval ktv; do_gettimeofday(&ktv); if (copy_to_user(tv, &ktv, sizeof(ktv))) return -EFAULT; } if (unlikely(tz != NULL)) { if (copy_to_user(tz, &sys_tz, sizeof(sys_tz))) return -EFAULT; } return 0; } /* kernlel/timer.c */ struct timespec xtime; void do_gettimeofday(struct timeval *tv) { struct timespec now; __get_realtime_clock_ts(&now); tv->tv_sec = now.tv_sec; tv->tv_usec = now.tv_nsec/1000; } static inline void __get_realtime_clock_ts(struct timespec *ts) { unsigned long seq; s64 nsecs; do { seq = read_seqbegin(&xtime_lock); *ts = xtime; nsecs = __get_nsec_offset(); } while (read_seqretry(&xtime_lock, seq)); timespec_add_ns(ts, nsecs); } static inline s64 __get_nsec_offset(void) { cycle_t cycle_now, cycle_delta; s64 ns_offset; /* read clocksource: */ cycle_now = clocksource_read(clock); /* calculate the delta since the last update_wall_time: */ cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; /* convert to nanoseconds: */ ns_offset = cyc2ns(clock, cycle_delta); return ns_offset; } static void update_wall_time(void) { ... xtime.tv_sec++; ... xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift; ... } static inline void update_times(unsigned long ticks) { update_wall_time(); calc_load(ticks); }
$B"!(BUnix callout$BBT$A9TNs(B
n tick $B8e$K!"4X?t$r
/$70c$&!#(B

$B8D!9$NMWAG$K!"(Bn tick $B8e$K $B@h$Kl=j$KCV$/!#(Btick $B$O!":9J,$GCV$/!#(B
tick $B$4$H$K!"@hF,$NCM$r8:$i$7$F$$$/!#(B
0 $B$K$J$C$?$i!"%-%e!<$+$i

$B"!Nc(B: 0 tick $B8e(B

10 tick $B8e$K(B f(x) $B$r 200 tick $B8e$K(B g(y) $B$r 200 tick $B8e$K(B h(z) $B$r

$B?^(B? callout $BBT$A9TNs(B(1)

$B"!Nc(B: 10 tick $B8e(B
f(x) $B$r
190 tick $B8e$K(B g(y) $B$r 190 tick $B8e$K(B h(z) $B$r

$B?^(B? callout $BBT$A9TNs(B(2)

$B"!Nc(B: 200 tick $B8e(B
g(y), h(z) $B$r

$B?^(B? callout $BBT$A9TNs(B(3)

$B"!(BLinux $B%?%$%^%j%9%H(B
include/linux/timer.h:
struct timer_list { struct list_head entry; unsigned long expires; void (*function)(unsigned long); unsigned long data; struct tvec_t_base_s *base; };

jiffies $B$,A}2C$7$F(B expires ($B@dBP;~9o(B)$B$KC#$9$l$P!"(B(*function)(data) $B$r8F$V!#(B
$B static inline void add_timer(struct timer_list *timer) { BUG_ON(timer_pending(timer)); __mod_timer(timer, timer->expires); } $BMxMQNc!#(B
timer->expires = jiffies + delay; timer->data = (unsigned long)data; timer->function = func; add_timer(timer);

$B"!(BLinux tv1..tv5
$BFbItE*$K$O!"(Btimer_list $B$O!"(Btv1$B$+$i(Btv5$B$N(B5$B$D$NI=$KJ,2r$5$l$FJ]B8$5$l$F$$$k!#(B

$B?^(B? Linux tv

tv1 $B$O!"(B256 (TVR_SIZE) $B%(%s%H%j!"(Btv2..tv5 $B$O!"(B64 $B%(%s%H%j(B (TVN_SIZE)$B!#(B
tv1 $B$O!"3F(B tick $B$KBP1~$7$F$$$k!#(B
$B%?%$%^3d$j9~$_$G!"(Bjiffies % 256 $B$K$"$k(B time_list $B$N%$%Y%s%H$r $B0l<~$7$?$i!"(Btv2 $B$K$"$k%$%Y%s%H$r(B tv1 $B$K0\F0$5$;$k!#(B

/* timer.c: */ static void run_timer_softirq(struct softirq_action *h) { tvec_base_t *base = __get_cpu_var(tvec_bases); hrtimer_run_queues(); if (time_after_eq(jiffies, base->timer_jiffies)) __run_timers(base); } static inline void __run_timers(tvec_base_t *base) { struct timer_list *timer; ... while (time_after_eq(jiffies, base->timer_jiffies)) { struct list_head work_list; struct list_head *head = &work_list; int index = base->timer_jiffies & TVR_MASK; ... ++base->timer_jiffies; list_replace_init(base->tv1.vec + index, &work_list); while (!list_empty(head)) { void (*fn)(unsigned long); unsigned long data; .. timer = list_entry(head->next,struct timer_list,entry); fn = timer->function; data = timer->data; ... fn(data); } } }

$B"!(Bdo_setitimer()

/* itimer.c */ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) { struct task_struct *tsk = current; struct hrtimer *timer; ... switch (which) { case ITIMER_REAL: ... timer = &tsk->signal->real_timer; ... tsk->signal->it_real_incr = timeval_to_ktime(value->it_interval); expires = timeval_to_ktime(value->it_value); if (expires.tv64 != 0) hrtimer_start(timer, expires, HRTIMER_REL); ... } } int hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) { ... base = lock_hrtimer_base(timer, &flags); new_base = switch_hrtimer_base(timer, base); timer->expires = tim; enqueue_hrtimer(timer, new_base); }
hrtimer $B$N4IM}$K$O!"LZ9=B$$,;H$o$l$F$$$k!#(BO(log n)$B!#(B
$B"!(Bscheduler_tick()

/* scheduler_tick() */ #define MIN_TIMESLICE max(5 * HZ / 1000, 1) #define DEF_TIMESLICE (100 * HZ / 1000) ... void scheduler_tick(void) { unsigned long long now = sched_clock(); struct task_struct *p = current; int cpu = smp_processor_id(); struct rq *rq = cpu_rq(cpu); update_cpu_clock(p, rq, now); rq->timestamp_last_tick = now; ... if (!--p->time_slice) { dequeue_task(p, rq->active); set_tsk_need_resched(p); p->prio = effective_prio(p); p->time_slice = task_timeslice(p); p->first_time_slice = 0; if (!rq->expired_timestamp) rq->expired_timestamp = jiffies; if (!TASK_INTERACTIVE(p) || expired_starving(rq)) { enqueue_task(p, rq->expired); if (p->static_prio < rq->best_expired_prio) rq->best_expired_prio = p->static_prio; } else enqueue_task(p, rq->active); } else { ... } ... }

Last updated: 2007/01/22 09:50:20

Yasushi Shinjo / <yas@is.tsukuba.ac.jp>