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Annotation of XNU/bsd/kern/kern_clock.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * The contents of this file constitute Original Code as defined in and
        !             7:  * are subject to the Apple Public Source License Version 1.1 (the
        !             8:  * "License").  You may not use this file except in compliance with the
        !             9:  * License.  Please obtain a copy of the License at
        !            10:  * http://www.apple.com/publicsource and read it before using this file.
        !            11:  * 
        !            12:  * This Original Code and all software distributed under the License are
        !            13:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            14:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            15:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            16:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            17:  * License for the specific language governing rights and limitations
        !            18:  * under the License.
        !            19:  * 
        !            20:  * @APPLE_LICENSE_HEADER_END@
        !            21:  */
        !            22: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
        !            23: /*-
        !            24:  * Copyright (c) 1982, 1986, 1991, 1993
        !            25:  *     The Regents of the University of California.  All rights reserved.
        !            26:  * (c) UNIX System Laboratories, Inc.
        !            27:  * All or some portions of this file are derived from material licensed
        !            28:  * to the University of California by American Telephone and Telegraph
        !            29:  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
        !            30:  * the permission of UNIX System Laboratories, Inc.
        !            31:  *
        !            32:  * Redistribution and use in source and binary forms, with or without
        !            33:  * modification, are permitted provided that the following conditions
        !            34:  * are met:
        !            35:  * 1. Redistributions of source code must retain the above copyright
        !            36:  *    notice, this list of conditions and the following disclaimer.
        !            37:  * 2. Redistributions in binary form must reproduce the above copyright
        !            38:  *    notice, this list of conditions and the following disclaimer in the
        !            39:  *    documentation and/or other materials provided with the distribution.
        !            40:  * 3. All advertising materials mentioning features or use of this software
        !            41:  *    must display the following acknowledgement:
        !            42:  *     This product includes software developed by the University of
        !            43:  *     California, Berkeley and its contributors.
        !            44:  * 4. Neither the name of the University nor the names of its contributors
        !            45:  *    may be used to endorse or promote products derived from this software
        !            46:  *    without specific prior written permission.
        !            47:  *
        !            48:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            49:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            50:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            51:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            52:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            53:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            54:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            55:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            56:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            57:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            58:  * SUCH DAMAGE.
        !            59:  *
        !            60:  *     @(#)kern_clock.c        8.5 (Berkeley) 1/21/94
        !            61:  */
        !            62: /*
        !            63:  * HISTORY
        !            64:  */
        !            65: 
        !            66: #include <machine/spl.h>
        !            67: 
        !            68: #include <sys/param.h>
        !            69: #include <sys/systm.h>
        !            70: #include <sys/time.h>
        !            71: #include <sys/dkstat.h>
        !            72: #include <sys/resourcevar.h>
        !            73: #include <sys/kernel.h>
        !            74: #include <sys/resource.h>
        !            75: #include <sys/proc.h>
        !            76: #include <sys/vm.h>
        !            77: 
        !            78: #ifdef GPROF
        !            79: #include <sys/gmon.h>
        !            80: #endif
        !            81: 
        !            82: #include <kern/thread.h>
        !            83: #include <kern/ast.h>
        !            84: #include <kern/assert.h>
        !            85: #include <mach/boolean.h>
        !            86: 
        !            87: /*
        !            88:  * Clock handling routines.
        !            89:  *
        !            90:  * This code is written to operate with two timers which run
        !            91:  * independently of each other. The main clock, running at hz
        !            92:  * times per second, is used to do scheduling and timeout calculations.
        !            93:  * The second timer does resource utilization estimation statistically
        !            94:  * based on the state of the machine phz times a second. Both functions
        !            95:  * can be performed by a single clock (ie hz == phz), however the 
        !            96:  * statistics will be much more prone to errors. Ideally a machine
        !            97:  * would have separate clocks measuring time spent in user state, system
        !            98:  * state, interrupt state, and idle state. These clocks would allow a non-
        !            99:  * approximate measure of resource utilization.
        !           100:  */
        !           101: 
        !           102: /*
        !           103:  * The hz hardware interval timer.
        !           104:  * We update the events relating to real time.
        !           105:  * If this timer is also being used to gather statistics,
        !           106:  * we run through the statistics gathering routine as well.
        !           107:  */
        !           108: 
        !           109: int bsd_hardclockinit = 0;
        !           110: /*ARGSUSED*/
        !           111: void
        !           112: bsd_hardclock(usermode, pc, numticks)
        !           113:        boolean_t usermode;
        !           114:        caddr_t pc;
        !           115:        int numticks;
        !           116: {
        !           117:        register struct proc *p;
        !           118:        register int s;
        !           119:        int ticks = numticks;
        !           120:        extern int tickdelta;
        !           121:        extern long timedelta;
        !           122:        register thread_t       thread;
        !           123: 
        !           124:        if (!bsd_hardclockinit)
        !           125:                return;
        !           126: 
        !           127:        thread = current_thread();
        !           128: 
        !           129:        /*
        !           130:         * Charge the time out based on the mode the cpu is in.
        !           131:         * Here again we fudge for the lack of proper interval timers
        !           132:         * assuming that the current state has been around at least
        !           133:         * one tick.
        !           134:         */
        !           135:        p = (struct proc *)get_bsdtask_info(current_task());
        !           136:        if (p && ((p->p_flag & P_WEXIT) == NULL)) {
        !           137:        if (usermode) {         
        !           138:                if (p) {
        !           139:                        if (p->p_stats && p->p_stats->p_prof.pr_scale) {
        !           140:                                p->p_flag |= P_OWEUPC;
        !           141:                                
        !           142: #if BSD_USE_APC
        !           143:     thread_set_apc(current_act(), bsd_ast);
        !           144: #else
        !           145:     ast_on(AST_BSD);
        !           146: #endif
        !           147: 
        !           148:                        }
        !           149:                }
        !           150: 
        !           151:                /*
        !           152:                 * CPU was in user state.  Increment
        !           153:                 * user time counter, and process process-virtual time
        !           154:                 * interval timer. 
        !           155:                 */
        !           156:                if (p->p_stats && 
        !           157:                timerisset(&p->p_stats->p_timer[ITIMER_VIRTUAL].it_value) &&
        !           158:                itimerdecr(&p->p_stats->p_timer[ITIMER_VIRTUAL], ticks) == 0)
        !           159:                        psignal(p, SIGVTALRM);
        !           160:        }
        !           161: 
        !           162:        /*
        !           163:         * If the cpu is currently scheduled to a process, then
        !           164:         * charge it with resource utilization for a tick, updating
        !           165:         * statistics which run in (user+system) virtual time,
        !           166:         * such as the cpu time limit and profiling timers.
        !           167:         * This assumes that the current process has been running
        !           168:         * the entire last tick.
        !           169:         */
        !           170:        if (p && !(is_thread_idle(thread)))
        !           171:        {               
        !           172:                if (p->p_limit && (p->p_limit->pl_rlimit[RLIMIT_CPU].rlim_cur != RLIM_INFINITY)) {
        !           173:                    time_value_t        sys_time, user_time;
        !           174: 
        !           175:                    thread_read_times(thread, &user_time, &sys_time);
        !           176:                    if ((sys_time.seconds + user_time.seconds + 1) >
        !           177:                        p->p_limit->pl_rlimit[RLIMIT_CPU].rlim_cur) {
        !           178:                        psignal(p, SIGXCPU);
        !           179:                        if (p->p_limit->pl_rlimit[RLIMIT_CPU].rlim_cur <
        !           180:                            p->p_limit->pl_rlimit[RLIMIT_CPU].rlim_max)
        !           181:                                p->p_limit->pl_rlimit[RLIMIT_CPU].rlim_cur += 5;
        !           182:                        }
        !           183:                }
        !           184:                if (timerisset(&p->p_stats->p_timer[ITIMER_PROF].it_value) &&
        !           185:                    itimerdecr(&p->p_stats->p_timer[ITIMER_PROF], ticks) == 0)
        !           186:                        psignal(p, SIGPROF);
        !           187:        }
        !           188: 
        !           189:        /*
        !           190:         * Increment the time-of-day, and schedule
        !           191:         * processing of the callouts at a very low cpu priority,
        !           192:         * so we don't keep the relatively high clock interrupt
        !           193:         * priority any longer than necessary.
        !           194:         */
        !           195: 
        !           196:        /*
        !           197:         * Gather the statistics.
        !           198:         */
        !           199:        gatherstats(usermode, pc);
        !           200: 
        !           201:        }
        !           202:        if (timedelta != 0) {
        !           203:                register delta;
        !           204:                clock_res_t nsdelta = tickdelta * NSEC_PER_USEC;
        !           205: 
        !           206:                if (timedelta < 0) {
        !           207:                        delta = ticks - tickdelta;
        !           208:                        timedelta += tickdelta;
        !           209:                        nsdelta = -nsdelta;
        !           210:                } else {
        !           211:                        delta = ticks + tickdelta;
        !           212:                        timedelta -= tickdelta;
        !           213:                }
        !           214:                clock_adjust_calendar(nsdelta);
        !           215:        }
        !           216:        microtime(&time);
        !           217: }
        !           218: 
        !           219: /*
        !           220:  * Gather statistics on resource utilization.
        !           221:  *
        !           222:  * We make a gross assumption: that the system has been in the
        !           223:  * state it is in (user state, kernel state, interrupt state,
        !           224:  * or idle state) for the entire last time interval, and
        !           225:  * update statistics accordingly.
        !           226:  */
        !           227: /*ARGSUSED*/
        !           228: void
        !           229: gatherstats(usermode, pc)
        !           230:        boolean_t usermode;
        !           231:        caddr_t pc;
        !           232: {
        !           233:        register int cpstate, s;
        !           234:        struct proc *proc =current_proc();
        !           235: #ifdef GPROF
        !           236:     struct gmonparam *p = &_gmonparam;
        !           237: #endif
        !           238: 
        !           239:        /*
        !           240:         * Determine what state the cpu is in.
        !           241:         */
        !           242:        if (usermode) {
        !           243:                /*
        !           244:                 * CPU was in user state.
        !           245:                 */
        !           246:                if (proc->p_nice > NZERO)
        !           247:                        cpstate = CP_NICE;
        !           248:                else
        !           249:                        cpstate = CP_USER;
        !           250:        } else {
        !           251:                /*
        !           252:                 * CPU was in system state.  If profiling kernel
        !           253:                 * increment a counter.  If no process is running
        !           254:                 * then this is a system tick if we were running
        !           255:                 * at a non-zero IPL (in a driver).  If a process is running,
        !           256:                 * then we charge it with system time even if we were
        !           257:                 * at a non-zero IPL, since the system often runs
        !           258:                 * this way during processing of system calls.
        !           259:                 * This is approximate, but the lack of true interval
        !           260:                 * timers makes doing anything else difficult.
        !           261:                 */
        !           262:                cpstate = CP_SYS;
        !           263:                if (is_thread_idle(current_thread()))
        !           264:                        cpstate = CP_IDLE;
        !           265: #ifdef GPROF
        !           266:                if (p->state == GMON_PROF_ON) {
        !           267:                        s = pc - p->lowpc;
        !           268:                        if (s < p->textsize) {
        !           269:                                s /= (HISTFRACTION * sizeof(*p->kcount));
        !           270:                                p->kcount[s]++;
        !           271:                        }
        !           272:                }
        !           273: #endif
        !           274:        }
        !           275:        /*
        !           276:         * We maintain statistics shown by user-level statistics
        !           277:         * programs:  the amount of time in each cpu state, and
        !           278:         * the amount of time each of DK_NDRIVE ``drives'' is busy.
        !           279:         */
        !           280:        cp_time[cpstate]++;
        !           281:        for (s = 0; s < DK_NDRIVE; s++)
        !           282:                if (dk_busy & (1 << s))
        !           283:                        dk_time[s]++;
        !           284: }
        !           285: 
        !           286: #if 0 /* (already in osfmk/mach_clock.c [ */
        !           287: /*
        !           288:  * Arrange that (*fun)(arg) is called in t/hz seconds.
        !           289:  */
        !           290: void
        !           291: timeout(ftn, arg, ticks)
        !           292:        void (*ftn) __P((void *));
        !           293:        void *arg;
        !           294:        register int ticks;
        !           295: {
        !           296:        thread_call_func_delayed(
        !           297:                (thread_call_func_t)ftn,
        !           298:                (thread_call_spec_t)arg,
        !           299:                        deadline_from_interval(ticks_to_tvalspec(ticks)));
        !           300: }
        !           301: 
        !           302: /*
        !           303:  * untimeout is called to remove a function timeout call
        !           304:  * from the callout structure.
        !           305:  */
        !           306: int
        !           307: untimeout(ftn, arg)
        !           308:        void (*ftn) __P((void *));
        !           309:        void *arg;
        !           310: {
        !           311:        thread_call_func_cancel(
        !           312:                (thread_call_func_t)ftn,
        !           313:                (thread_call_spec_t)arg, FALSE);
        !           314: 
        !           315:        return TRUE;    /* XXX cheat */
        !           316: }
        !           317: #endif /* 0 ] */
        !           318: /*
        !           319:  * Compute number of hz until specified time.
        !           320:  * Used to compute third argument to timeout() from an
        !           321:  * absolute time.
        !           322:  */
        !           323: hzto(tv)
        !           324:        struct timeval *tv;
        !           325: {
        !           326:        register long ticks;
        !           327:        register long sec;
        !           328:        int s = splhigh();
        !           329:        
        !           330:        /*
        !           331:         * If number of milliseconds will fit in 32 bit arithmetic,
        !           332:         * then compute number of milliseconds to time and scale to
        !           333:         * ticks.  Otherwise just compute number of hz in time, rounding
        !           334:         * times greater than representible to maximum value.
        !           335:         *
        !           336:         * Delta times less than 25 days can be computed ``exactly''.
        !           337:         * Maximum value for any timeout in 10ms ticks is 250 days.
        !           338:         */
        !           339:        sec = tv->tv_sec - time.tv_sec;
        !           340:        if (sec <= 0x7fffffff / 1000 - 1000)
        !           341:                ticks = ((tv->tv_sec - time.tv_sec) * 1000 +
        !           342:                        (tv->tv_usec - time.tv_usec) / 1000)
        !           343:                                / (tick / 1000);
        !           344:        else if (sec <= 0x7fffffff / hz)
        !           345:                ticks = sec * hz;
        !           346:        else
        !           347:                ticks = 0x7fffffff;
        !           348:        splx(s);
        !           349:        return (ticks);
        !           350: }
        !           351: 
        !           352: #if 0 /* [ */
        !           353: /*
        !           354:  * Convert ticks to a timeval
        !           355:  */
        !           356: ticks_to_timeval(ticks, tvp)
        !           357:        register long ticks;
        !           358:        struct timeval *tvp;
        !           359: {
        !           360:        tvp->tv_sec = ticks/hz;
        !           361:        tvp->tv_usec = (ticks%hz) * tick;
        !           362:        asert(tvp->tv_usec < 1000000);
        !           363: }
        !           364: #endif /* ] */
        !           365: 
        !           366: /*
        !           367:  * Return information about system clocks.
        !           368:  */
        !           369: int
        !           370: sysctl_clockrate(where, sizep)
        !           371:        register char *where;
        !           372:        size_t *sizep;
        !           373: {
        !           374:        struct clockinfo clkinfo;
        !           375: 
        !           376:        /*
        !           377:         * Construct clockinfo structure.
        !           378:         */
        !           379:        clkinfo.hz = hz;
        !           380:        clkinfo.tick = tick;
        !           381:        clkinfo.profhz = hz;
        !           382:        clkinfo.stathz = hz;
        !           383:        return sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo));
        !           384: }
        !           385: 
        !           386: 
        !           387: /*
        !           388:  * Compute number of ticks in the specified amount of time.
        !           389:  */
        !           390: int
        !           391: tvtohz(tv)
        !           392:        struct timeval *tv;
        !           393: {
        !           394:        register unsigned long ticks;
        !           395:        register long sec, usec;
        !           396: 
        !           397:        /*
        !           398:         * If the number of usecs in the whole seconds part of the time
        !           399:         * difference fits in a long, then the total number of usecs will
        !           400:         * fit in an unsigned long.  Compute the total and convert it to
        !           401:         * ticks, rounding up and adding 1 to allow for the current tick
        !           402:         * to expire.  Rounding also depends on unsigned long arithmetic
        !           403:         * to avoid overflow.
        !           404:         *
        !           405:         * Otherwise, if the number of ticks in the whole seconds part of
        !           406:         * the time difference fits in a long, then convert the parts to
        !           407:         * ticks separately and add, using similar rounding methods and
        !           408:         * overflow avoidance.  This method would work in the previous
        !           409:         * case but it is slightly slower and assumes that hz is integral.
        !           410:         *
        !           411:         * Otherwise, round the time difference down to the maximum
        !           412:         * representable value.
        !           413:         *
        !           414:         * If ints have 32 bits, then the maximum value for any timeout in
        !           415:         * 10ms ticks is 248 days.
        !           416:         */
        !           417:        sec = tv->tv_sec;
        !           418:        usec = tv->tv_usec;
        !           419:        if (usec < 0) {
        !           420:                sec--;
        !           421:                usec += 1000000;
        !           422:        }
        !           423:        if (sec < 0) {
        !           424: #ifdef DIAGNOSTIC
        !           425:                if (usec > 0) {
        !           426:                        sec++;
        !           427:                        usec -= 1000000;
        !           428:                }
        !           429:                printf("tvotohz: negative time difference %ld sec %ld usec\n",
        !           430:                       sec, usec);
        !           431: #endif
        !           432:                ticks = 1;
        !           433:        } else if (sec <= LONG_MAX / 1000000)
        !           434:                ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1))
        !           435:                        / tick + 1;
        !           436:        else if (sec <= LONG_MAX / hz)
        !           437:                ticks = sec * hz
        !           438:                        + ((unsigned long)usec + (tick - 1)) / tick + 1;
        !           439:        else
        !           440:                ticks = LONG_MAX;
        !           441:        if (ticks > INT_MAX)
        !           442:                ticks = INT_MAX;
        !           443:        return ((int)ticks);
        !           444: }
        !           445: 
        !           446: 
        !           447: /*
        !           448:  * Start profiling on a process.
        !           449:  *
        !           450:  * Kernel profiling passes kernel_proc which never exits and hence
        !           451:  * keeps the profile clock running constantly.
        !           452:  */
        !           453: void
        !           454: startprofclock(p)
        !           455:        register struct proc *p;
        !           456: {
        !           457:        if ((p->p_flag & P_PROFIL) == 0)
        !           458:                p->p_flag |= P_PROFIL;
        !           459: }
        !           460: 
        !           461: /*
        !           462:  * Stop profiling on a process.
        !           463:  */
        !           464: void
        !           465: stopprofclock(p)
        !           466:        register struct proc *p;
        !           467: {
        !           468:        if (p->p_flag & P_PROFIL)
        !           469:                p->p_flag &= ~P_PROFIL;
        !           470: }
        !           471: 
        !           472: void
        !           473: bsd_uprofil(struct time_value *syst, unsigned int pc)
        !           474: {
        !           475: struct proc *p = current_proc();
        !           476: int            ticks;
        !           477: struct timeval *tv;
        !           478: struct timeval st;
        !           479: 
        !           480:        if (p == NULL)
        !           481:                return;
        !           482:        if ( !(p->p_flag & P_PROFIL))
        !           483:                return;
        !           484: 
        !           485:        st.tv_sec = syst->seconds;
        !           486:        st.tv_usec = syst->microseconds;
        !           487: 
        !           488:        tv = &(p->p_stats->p_ru.ru_stime);
        !           489: 
        !           490:        ticks = ((tv->tv_sec - st.tv_sec) * 1000 +
        !           491:                (tv->tv_usec - st.tv_usec) / 1000) /
        !           492:                (tick / 1000);
        !           493:        if (ticks)
        !           494:                addupc_task(p, pc, ticks);
        !           495: }
        !           496: 
        !           497: void
        !           498: get_procrustime(time_value_t *tv)
        !           499: {
        !           500:        struct proc *p = current_proc();
        !           501:        struct timeval st;
        !           502: 
        !           503:        if (p == NULL) 
        !           504:                return;
        !           505:        if ( !(p->p_flag & P_PROFIL))
        !           506:                return;
        !           507: 
        !           508:        st = p->p_stats->p_ru.ru_stime;
        !           509:        
        !           510:        tv->seconds = st.tv_sec;
        !           511:        tv->microseconds = st.tv_usec;
        !           512: }

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