/*- * 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 * $FreeBSD$ */ #include "opt_ntp.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef GPROF #include #endif static void initclocks __P((void *dummy)); SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL) /* Some of these don't belong here, but it's easiest to concentrate them. */ long cp_time[CPUSTATES]; SYSCTL_OPAQUE(_kern, OID_AUTO, cp_time, CTLFLAG_RD, &cp_time, sizeof(cp_time), "LU", "CPU time statistics"); long tk_cancc; long tk_nin; long tk_nout; long tk_rawcc; /* * 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; } /* * Each time the real-time timer fires, this function is called on all CPUs * with each CPU passing in its curproc as the first argument. If possible * a nice optimization in the future would be to allow the CPU receiving the * actual real-time timer interrupt to call this function on behalf of the * other CPUs rather than sending an IPI to all other CPUs so that they * can call this function. Note that hardclock() calls hardclock_process() * for the CPU receiving the timer interrupt, so only the other CPUs in the * system need to call this function (or have it called on their behalf. */ void hardclock_process(p, user) struct proc *p; int user; { struct pstats *pstats; /* * Run current process's virtual and profile time, as needed. */ mtx_assert(&sched_lock, MA_OWNED); pstats = p->p_stats; if (user && timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) && itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) { p->p_sflag |= PS_ALRMPEND; aston(p); } if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) && itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) { p->p_sflag |= PS_PROFPEND; aston(p); } } /* * The real-time timer, interrupting hz times per second. */ void hardclock(frame) register struct clockframe *frame; { int need_softclock = 0; CTR0(KTR_INTR, "hardclock fired"); mtx_lock_spin(&sched_lock); hardclock_process(curproc, CLKF_USERMODE(frame)); mtx_unlock_spin(&sched_lock); /* * If no separate statistics clock is available, run it from here. * * XXX: this only works for UP */ if (stathz == 0) statclock(frame); tc_windup(); /* * Process callouts at a very low cpu priority, so we don't keep the * relatively high clock interrupt priority any longer than necessary. */ mtx_lock_spin(&callout_lock); ticks++; if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) { need_softclock = 1; } else if (softticks + 1 == ticks) ++softticks; mtx_unlock_spin(&callout_lock); /* * swi_sched acquires sched_lock, so we don't want to call it with * callout_lock held; incorrect locking order. */ if (need_softclock) swi_sched(softclock_ih, SWI_NOSWITCH); } /* * 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; /* * XXX; Right now sched_lock protects statclock(), but perhaps * it should be protected later on by a time_lock, which would * cover psdiv, etc. as well. */ mtx_lock_spin(&sched_lock); if ((p->p_sflag & PS_PROFIL) == 0) { p->p_sflag |= PS_PROFIL; if (++profprocs == 1 && stathz != 0) { s = splstatclock(); psdiv = pscnt = psratio; setstatclockrate(profhz); splx(s); } } mtx_unlock_spin(&sched_lock); } /* * Stop profiling on a process. */ void stopprofclock(p) register struct proc *p; { int s; mtx_lock_spin(&sched_lock); if (p->p_sflag & PS_PROFIL) { p->p_sflag &= ~PS_PROFIL; if (--profprocs == 0 && stathz != 0) { s = splstatclock(); psdiv = pscnt = 1; setstatclockrate(stathz); splx(s); } } mtx_unlock_spin(&sched_lock); } /* * Do process and kernel statistics. Most of the statistics are only * used by user-level statistics programs. The main exceptions are * p->p_uticks, p->p_sticks, p->p_iticks, and p->p_estcpu. This function * should be called by all CPUs in the system for each statistics clock * interrupt. See the description of hardclock_process for more detail on * this function's relationship to statclock. */ void statclock_process(p, pc, user) struct proc *p; register_t pc; int user; { #ifdef GPROF struct gmonparam *g; int i; #endif struct pstats *pstats; long rss; struct rusage *ru; struct vmspace *vm; KASSERT(p == curproc, ("statclock_process: p != curproc")); mtx_assert(&sched_lock, MA_OWNED); if (user) { /* * Came from user mode; CPU was in user state. * If this process is being profiled, record the tick. */ if (p->p_sflag & PS_PROFIL) addupc_intr(p, pc, 1); if (pscnt < psdiv) return; /* * Charge the time as appropriate. */ 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 = pc - g->lowpc; if (i < g->textsize) { i /= HISTFRACTION * sizeof(*g->kcount); g->kcount[i]++; } } #endif if (pscnt < psdiv) 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. */ if ((p->p_ithd != NULL) || p->p_intr_nesting_level >= 2) { p->p_iticks++; cp_time[CP_INTR]++; } else { p->p_sticks++; if (p != PCPU_GET(idleproc)) cp_time[CP_SYS]++; else cp_time[CP_IDLE]++; } } schedclock(p); /* 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; } } /* * Statistics clock. Grab profile sample, and if divider reaches 0, * do process and kernel statistics. Most of the statistics are only * used by user-level statistics programs. The main exceptions are * p->p_uticks, p->p_sticks, p->p_iticks, and p->p_estcpu. */ void statclock(frame) register struct clockframe *frame; { CTR0(KTR_INTR, "statclock fired"); mtx_lock_spin(&sched_lock); if (--pscnt == 0) pscnt = psdiv; statclock_process(curproc, CLKF_PC(frame), CLKF_USERMODE(frame)); mtx_unlock_spin(&sched_lock); } /* * 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","");