/*- * Copyright (c) 1997, 1998 Poul-Henning Kamp * Copyright (c) 1982, 1986, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 * $Id: kern_clock.c,v 1.87 1999/02/19 14:25:34 luoqi Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef GPROF #include #endif #if defined(SMP) && defined(BETTER_CLOCK) #include #endif /* This is where the NTIMECOUNTER option hangs out */ #include "opt_ntp.h" /* * Number of timecounters used to implement stable storage */ #ifndef NTIMECOUNTER #define NTIMECOUNTER 5 #endif static MALLOC_DEFINE(M_TIMECOUNTER, "timecounter", "Timecounter stable storage"); static void initclocks __P((void *dummy)); SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL) static void tco_forward __P((int force)); static void tco_setscales __P((struct timecounter *tc)); static __inline unsigned tco_delta __P((struct timecounter *tc)); /* Some of these don't belong here, but it's easiest to concentrate them. */ #if defined(SMP) && defined(BETTER_CLOCK) long cp_time[CPUSTATES]; #else static long cp_time[CPUSTATES]; #endif long tk_cancc; long tk_nin; long tk_nout; long tk_rawcc; time_t time_second; /* * Which update policy to use. * 0 - every tick, bad hardware may fail with "calcru negative..." * 1 - more resistent to the above hardware, but less efficient. */ static int tco_method; /* * Implement a dummy timecounter which we can use until we get a real one * in the air. This allows the console and other early stuff to use * timeservices. */ static unsigned dummy_get_timecount(struct timecounter *tc) { static unsigned now; return (++now); } static struct timecounter dummy_timecounter = { dummy_get_timecount, 0, ~0u, 1000000, "dummy" }; struct timecounter *timecounter = &dummy_timecounter; /* * Clock handling routines. * * This code is written to operate with two timers that run independently of * each other. * * The main timer, running hz times per second, is used to trigger interval * timers, timeouts and rescheduling as needed. * * The second timer handles kernel and user profiling, * and does resource use estimation. If the second timer is programmable, * it is randomized to avoid aliasing between the two clocks. For example, * the randomization prevents an adversary from always giving up the cpu * just before its quantum expires. Otherwise, it would never accumulate * cpu ticks. The mean frequency of the second timer is stathz. * * If no second timer exists, stathz will be zero; in this case we drive * profiling and statistics off the main clock. This WILL NOT be accurate; * do not do it unless absolutely necessary. * * The statistics clock may (or may not) be run at a higher rate while * profiling. This profile clock runs at profhz. We require that profhz * be an integral multiple of stathz. * * If the statistics clock is running fast, it must be divided by the ratio * profhz/stathz for statistics. (For profiling, every tick counts.) * * Time-of-day is maintained using a "timecounter", which may or may * not be related to the hardware generating the above mentioned * interrupts. */ int stathz; int profhz; static int profprocs; int ticks; static int psdiv, pscnt; /* prof => stat divider */ int psratio; /* ratio: prof / stat */ /* * Initialize clock frequencies and start both clocks running. */ /* ARGSUSED*/ static void initclocks(dummy) void *dummy; { register int i; /* * Set divisors to 1 (normal case) and let the machine-specific * code do its bit. */ psdiv = pscnt = 1; cpu_initclocks(); /* * Compute profhz/stathz, and fix profhz if needed. */ i = stathz ? stathz : hz; if (profhz == 0) profhz = i; psratio = profhz / i; } /* * The real-time timer, interrupting hz times per second. */ void hardclock(frame) register struct clockframe *frame; { register struct proc *p; p = curproc; if (p) { register struct pstats *pstats; /* * Run current process's virtual and profile time, as needed. */ pstats = p->p_stats; if (CLKF_USERMODE(frame) && timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) && itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) psignal(p, SIGVTALRM); if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) && itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) psignal(p, SIGPROF); } #if defined(SMP) && defined(BETTER_CLOCK) forward_hardclock(pscnt); #endif /* * If no separate statistics clock is available, run it from here. */ if (stathz == 0) statclock(frame); tco_forward(0); ticks++; /* * Process callouts at a very low cpu priority, so we don't keep the * relatively high clock interrupt priority any longer than necessary. */ if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) { if (CLKF_BASEPRI(frame)) { /* * Save the overhead of a software interrupt; * it will happen as soon as we return, so do it now. */ (void)splsoftclock(); softclock(); } else setsoftclock(); } else if (softticks + 1 == ticks) ++softticks; } /* * Compute number of ticks in the specified amount of time. */ int tvtohz(tv) struct timeval *tv; { register unsigned long ticks; register long sec, usec; /* * If the number of usecs in the whole seconds part of the time * difference fits in a long, then the total number of usecs will * fit in an unsigned long. Compute the total and convert it to * ticks, rounding up and adding 1 to allow for the current tick * to expire. Rounding also depends on unsigned long arithmetic * to avoid overflow. * * Otherwise, if the number of ticks in the whole seconds part of * the time difference fits in a long, then convert the parts to * ticks separately and add, using similar rounding methods and * overflow avoidance. This method would work in the previous * case but it is slightly slower and assumes that hz is integral. * * Otherwise, round the time difference down to the maximum * representable value. * * If ints have 32 bits, then the maximum value for any timeout in * 10ms ticks is 248 days. */ sec = tv->tv_sec; usec = tv->tv_usec; if (usec < 0) { sec--; usec += 1000000; } if (sec < 0) { #ifdef DIAGNOSTIC if (usec > 0) { sec++; usec -= 1000000; } printf("tvotohz: negative time difference %ld sec %ld usec\n", sec, usec); #endif ticks = 1; } else if (sec <= LONG_MAX / 1000000) ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1)) / tick + 1; else if (sec <= LONG_MAX / hz) ticks = sec * hz + ((unsigned long)usec + (tick - 1)) / tick + 1; else ticks = LONG_MAX; if (ticks > INT_MAX) ticks = INT_MAX; return ((int)ticks); } /* * Start profiling on a process. * * Kernel profiling passes proc0 which never exits and hence * keeps the profile clock running constantly. */ void startprofclock(p) register struct proc *p; { int s; if ((p->p_flag & P_PROFIL) == 0) { p->p_flag |= P_PROFIL; if (++profprocs == 1 && stathz != 0) { s = splstatclock(); psdiv = pscnt = psratio; setstatclockrate(profhz); splx(s); } } } /* * Stop profiling on a process. */ void stopprofclock(p) register struct proc *p; { int s; if (p->p_flag & P_PROFIL) { p->p_flag &= ~P_PROFIL; if (--profprocs == 0 && stathz != 0) { s = splstatclock(); psdiv = pscnt = 1; setstatclockrate(stathz); splx(s); } } } /* * Statistics clock. Grab profile sample, and if divider reaches 0, * do process and kernel statistics. */ void statclock(frame) register struct clockframe *frame; { #ifdef GPROF register struct gmonparam *g; int i; #endif register struct proc *p; struct pstats *pstats; long rss; struct rusage *ru; struct vmspace *vm; if (curproc != NULL && CLKF_USERMODE(frame)) { p = curproc; if (p->p_flag & P_PROFIL) addupc_intr(p, CLKF_PC(frame), 1); #if defined(SMP) && defined(BETTER_CLOCK) if (stathz != 0) forward_statclock(pscnt); #endif if (--pscnt > 0) return; /* * Came from user mode; CPU was in user state. * If this process is being profiled record the tick. */ p->p_uticks++; if (p->p_nice > NZERO) cp_time[CP_NICE]++; else cp_time[CP_USER]++; } else { #ifdef GPROF /* * Kernel statistics are just like addupc_intr, only easier. */ g = &_gmonparam; if (g->state == GMON_PROF_ON) { i = CLKF_PC(frame) - g->lowpc; if (i < g->textsize) { i /= HISTFRACTION * sizeof(*g->kcount); g->kcount[i]++; } } #endif #if defined(SMP) && defined(BETTER_CLOCK) if (stathz != 0) forward_statclock(pscnt); #endif if (--pscnt > 0) return; /* * Came from kernel mode, so we were: * - handling an interrupt, * - doing syscall or trap work on behalf of the current * user process, or * - spinning in the idle loop. * Whichever it is, charge the time as appropriate. * Note that we charge interrupts to the current process, * regardless of whether they are ``for'' that process, * so that we know how much of its real time was spent * in ``non-process'' (i.e., interrupt) work. */ p = curproc; if (CLKF_INTR(frame)) { if (p != NULL) p->p_iticks++; cp_time[CP_INTR]++; } else if (p != NULL) { p->p_sticks++; cp_time[CP_SYS]++; } else cp_time[CP_IDLE]++; } pscnt = psdiv; /* * We maintain statistics shown by user-level statistics * programs: the amount of time in each cpu state. */ /* * We adjust the priority of the current process. The priority of * a process gets worse as it accumulates CPU time. The cpu usage * estimator (p_estcpu) is increased here. The formula for computing * priorities (in kern_synch.c) will compute a different value each * time p_estcpu increases by 4. The cpu usage estimator ramps up * quite quickly when the process is running (linearly), and decays * away exponentially, at a rate which is proportionally slower when * the system is busy. The basic principal is that the system will * 90% forget that the process used a lot of CPU time in 5 * loadav * seconds. This causes the system to favor processes which haven't * run much recently, and to round-robin among other processes. */ if (p != NULL) { p->p_cpticks++; if (++p->p_estcpu == 0) p->p_estcpu--; if ((p->p_estcpu & 3) == 0) { resetpriority(p); if (p->p_priority >= PUSER) p->p_priority = p->p_usrpri; } /* Update resource usage integrals and maximums. */ if ((pstats = p->p_stats) != NULL && (ru = &pstats->p_ru) != NULL && (vm = p->p_vmspace) != NULL) { ru->ru_ixrss += pgtok(vm->vm_tsize); ru->ru_idrss += pgtok(vm->vm_dsize); ru->ru_isrss += pgtok(vm->vm_ssize); rss = pgtok(vmspace_resident_count(vm)); if (ru->ru_maxrss < rss) ru->ru_maxrss = rss; } } } /* * Return information about system clocks. */ static int sysctl_kern_clockrate SYSCTL_HANDLER_ARGS { struct clockinfo clkinfo; /* * Construct clockinfo structure. */ clkinfo.hz = hz; clkinfo.tick = tick; clkinfo.tickadj = tickadj; clkinfo.profhz = profhz; clkinfo.stathz = stathz ? stathz : hz; return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req)); } SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD, 0, 0, sysctl_kern_clockrate, "S,clockinfo",""); static __inline unsigned tco_delta(struct timecounter *tc) { return ((tc->tc_get_timecount(tc) - tc->tc_offset_count) & tc->tc_counter_mask); } /* * We have four functions for looking at the clock, two for microseconds * and two for nanoseconds. For each there is fast but less precise * version "get{nano|micro}time" which will return a time which is up * to 1/HZ previous to the call, whereas the raw version "{nano|micro}time" * will return a timestamp which is as precise as possible. */ void getmicrotime(struct timeval *tvp) { struct timecounter *tc; if (!tco_method) { tc = timecounter; *tvp = tc->tc_microtime; } else { microtime(tvp); } } void getnanotime(struct timespec *tsp) { struct timecounter *tc; if (!tco_method) { tc = timecounter; *tsp = tc->tc_nanotime; } else { nanotime(tsp); } } void microtime(struct timeval *tv) { struct timecounter *tc; tc = (struct timecounter *)timecounter; tv->tv_sec = tc->tc_offset_sec; tv->tv_usec = tc->tc_offset_micro; tv->tv_usec += ((u_int64_t)tco_delta(tc) * tc->tc_scale_micro) >> 32; tv->tv_usec += boottime.tv_usec; tv->tv_sec += boottime.tv_sec; while (tv->tv_usec >= 1000000) { tv->tv_usec -= 1000000; tv->tv_sec++; } } void nanotime(struct timespec *ts) { unsigned count; u_int64_t delta; struct timecounter *tc; tc = (struct timecounter *)timecounter; ts->tv_sec = tc->tc_offset_sec; count = tco_delta(tc); delta = tc->tc_offset_nano; delta += ((u_int64_t)count * tc->tc_scale_nano_f); delta >>= 32; delta += ((u_int64_t)count * tc->tc_scale_nano_i); delta += boottime.tv_usec * 1000; ts->tv_sec += boottime.tv_sec; while (delta >= 1000000000) { delta -= 1000000000; ts->tv_sec++; } ts->tv_nsec = delta; } void timecounter_timespec(unsigned count, struct timespec *ts) { u_int64_t delta; struct timecounter *tc; tc = (struct timecounter *)timecounter; ts->tv_sec = tc->tc_offset_sec; count -= tc->tc_offset_count; count &= tc->tc_counter_mask; delta = tc->tc_offset_nano; delta += ((u_int64_t)count * tc->tc_scale_nano_f); delta >>= 32; delta += ((u_int64_t)count * tc->tc_scale_nano_i); delta += boottime.tv_usec * 1000; ts->tv_sec += boottime.tv_sec; while (delta >= 1000000000) { delta -= 1000000000; ts->tv_sec++; } ts->tv_nsec = delta; } void getmicrouptime(struct timeval *tvp) { struct timecounter *tc; if (!tco_method) { tc = timecounter; tvp->tv_sec = tc->tc_offset_sec; tvp->tv_usec = tc->tc_offset_micro; } else { microuptime(tvp); } } void getnanouptime(struct timespec *tsp) { struct timecounter *tc; if (!tco_method) { tc = timecounter; tsp->tv_sec = tc->tc_offset_sec; tsp->tv_nsec = tc->tc_offset_nano >> 32; } else { nanouptime(tsp); } } void microuptime(struct timeval *tv) { struct timecounter *tc; tc = (struct timecounter *)timecounter; tv->tv_sec = tc->tc_offset_sec; tv->tv_usec = tc->tc_offset_micro; tv->tv_usec += ((u_int64_t)tco_delta(tc) * tc->tc_scale_micro) >> 32; if (tv->tv_usec >= 1000000) { tv->tv_usec -= 1000000; tv->tv_sec++; } } void nanouptime(struct timespec *ts) { unsigned count; u_int64_t delta; struct timecounter *tc; tc = (struct timecounter *)timecounter; ts->tv_sec = tc->tc_offset_sec; count = tco_delta(tc); delta = tc->tc_offset_nano; delta += ((u_int64_t)count * tc->tc_scale_nano_f); delta >>= 32; delta += ((u_int64_t)count * tc->tc_scale_nano_i); if (delta >= 1000000000) { delta -= 1000000000; ts->tv_sec++; } ts->tv_nsec = delta; } static void tco_setscales(struct timecounter *tc) { u_int64_t scale; scale = 1000000000LL << 32; if (tc->tc_adjustment > 0) scale += (tc->tc_adjustment * 1000LL) << 10; else scale -= (-tc->tc_adjustment * 1000LL) << 10; scale /= tc->tc_frequency; tc->tc_scale_micro = scale / 1000; tc->tc_scale_nano_f = scale & 0xffffffff; tc->tc_scale_nano_i = scale >> 32; } void init_timecounter(struct timecounter *tc) { struct timespec ts1; struct timecounter *t1, *t2, *t3; int i; tc->tc_adjustment = 0; tco_setscales(tc); tc->tc_offset_count = tc->tc_get_timecount(tc); tc->tc_tweak = tc; MALLOC(t1, struct timecounter *, sizeof *t1, M_TIMECOUNTER, M_WAITOK); *t1 = *tc; t2 = t1; for (i = 1; i < NTIMECOUNTER; i++) { MALLOC(t3, struct timecounter *, sizeof *t3, M_TIMECOUNTER, M_WAITOK); *t3 = *tc; t3->tc_other = t2; t2 = t3; } t1->tc_other = t3; tc = t1; printf("Timecounter \"%s\" frequency %lu Hz\n", tc->tc_name, (u_long)tc->tc_frequency); /* XXX: For now always start using the counter. */ tc->tc_offset_count = tc->tc_get_timecount(tc); nanouptime(&ts1); tc->tc_offset_nano = (u_int64_t)ts1.tv_nsec << 32; tc->tc_offset_micro = ts1.tv_nsec / 1000; tc->tc_offset_sec = ts1.tv_sec; timecounter = tc; } void set_timecounter(struct timespec *ts) { struct timespec ts2; nanouptime(&ts2); boottime.tv_sec = ts->tv_sec - ts2.tv_sec; boottime.tv_usec = (ts->tv_nsec - ts2.tv_nsec) / 1000; if (boottime.tv_usec < 0) { boottime.tv_usec += 1000000; boottime.tv_sec--; } /* fiddle all the little crinkly bits around the fiords... */ tco_forward(1); } #if 0 /* Currently unused */ void switch_timecounter(struct timecounter *newtc) { int s; struct timecounter *tc; struct timespec ts; s = splclock(); tc = timecounter; if (newtc == tc || newtc == tc->tc_other) { splx(s); return; } nanouptime(&ts); newtc->tc_offset_sec = ts.tv_sec; newtc->tc_offset_nano = (u_int64_t)ts.tv_nsec << 32; newtc->tc_offset_micro = ts.tv_nsec / 1000; newtc->tc_offset_count = newtc->tc_get_timecount(newtc); timecounter = newtc; splx(s); } #endif static struct timecounter * sync_other_counter(void) { struct timecounter *tc, *tcn, *tco; unsigned delta; tco = timecounter; tc = tco->tc_other; tcn = tc->tc_other; *tc = *tco; tc->tc_other = tcn; delta = tco_delta(tc); tc->tc_offset_count += delta; tc->tc_offset_count &= tc->tc_counter_mask; tc->tc_offset_nano += (u_int64_t)delta * tc->tc_scale_nano_f; tc->tc_offset_nano += (u_int64_t)delta * tc->tc_scale_nano_i << 32; return (tc); } static void tco_forward(int force) { struct timecounter *tc, *tco; tco = timecounter; tc = sync_other_counter(); /* * We may be inducing a tiny error here, the tc_poll_pps() may * process a latched count which happens after the tco_delta() * in sync_other_counter(), which would extend the previous * counters parameters into the domain of this new one. * Since the timewindow is very small for this, the error is * going to be only a few weenieseconds (as Dave Mills would * say), so lets just not talk more about it, OK ? */ if (tco->tc_poll_pps) tco->tc_poll_pps(tco); if (timedelta != 0) { tc->tc_offset_nano += (u_int64_t)(tickdelta * 1000) << 32; timedelta -= tickdelta; force++; } while (tc->tc_offset_nano >= 1000000000ULL << 32) { tc->tc_offset_nano -= 1000000000ULL << 32; tc->tc_offset_sec++; tc->tc_frequency = tc->tc_tweak->tc_frequency; tc->tc_adjustment = tc->tc_tweak->tc_adjustment; ntp_update_second(tc); /* XXX only needed if xntpd runs */ tco_setscales(tc); force++; } if (tco_method && !force) return; tc->tc_offset_micro = (tc->tc_offset_nano / 1000) >> 32; /* Figure out the wall-clock time */ tc->tc_nanotime.tv_sec = tc->tc_offset_sec + boottime.tv_sec; tc->tc_nanotime.tv_nsec = (tc->tc_offset_nano >> 32) + boottime.tv_usec * 1000; tc->tc_microtime.tv_usec = tc->tc_offset_micro + boottime.tv_usec; if (tc->tc_nanotime.tv_nsec >= 1000000000) { tc->tc_nanotime.tv_nsec -= 1000000000; tc->tc_microtime.tv_usec -= 1000000; tc->tc_nanotime.tv_sec++; } time_second = tc->tc_microtime.tv_sec = tc->tc_nanotime.tv_sec; timecounter = tc; } static int sysctl_kern_timecounter_frequency SYSCTL_HANDLER_ARGS { return (sysctl_handle_opaque(oidp, &timecounter->tc_tweak->tc_frequency, sizeof(timecounter->tc_tweak->tc_frequency), req)); } static int sysctl_kern_timecounter_adjustment SYSCTL_HANDLER_ARGS { return (sysctl_handle_opaque(oidp, &timecounter->tc_tweak->tc_adjustment, sizeof(timecounter->tc_tweak->tc_adjustment), req)); } SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, ""); SYSCTL_INT(_kern_timecounter, KERN_ARGMAX, method, CTLFLAG_RW, &tco_method, 0, "This variable determines the method used for updating timecounters. " "If the default algorithm (0) fails with \"calcru negative...\" messages " "try the alternate algorithm (1) which handles bad hardware better." ); SYSCTL_PROC(_kern_timecounter, OID_AUTO, frequency, CTLTYPE_INT | CTLFLAG_RW, 0, sizeof(u_int), sysctl_kern_timecounter_frequency, "I", ""); SYSCTL_PROC(_kern_timecounter, OID_AUTO, adjustment, CTLTYPE_INT | CTLFLAG_RW, 0, sizeof(int), sysctl_kern_timecounter_adjustment, "I", "");