/* * Copyright (c) 1997-1998 University of Utah and the Flux Group. * All rights reserved. * * This file is part of the Flux OSKit. The OSKit is free software, also known * as "open source;" you can redistribute it and/or modify it under the terms * of the GNU General Public License (GPL), version 2, as published by the Free * Software Foundation (FSF). To explore alternate licensing terms, contact * the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271. * * The OSKit is distributed in the hope that it will be useful, but WITHOUT ANY * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GPL for more details. You should have * received a copy of the GPL along with the OSKit; see the file COPYING. If * not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA. */ /* * I am having no mercy with this file. * I ripped out everything I didn't need */ /*- * 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 1.26 1996/07/30 16:59:22 bde Exp $ */ /* Portions of this software are covered by the following: */ /****************************************************************************** * * * Copyright (c) David L. Mills 1993, 1994 * * * * Permission to use, copy, modify, and distribute this software and its * * documentation for any purpose and without fee is hereby granted, provided * * that the above copyright notice appears in all copies and that both the * * copyright notice and this permission notice appear in supporting * * documentation, and that the name University of Delaware not be used in * * advertising or publicity pertaining to distribution of the software * * without specific, written prior permission. The University of Delaware * * makes no representations about the suitability this software for any * * purpose. It is provided "as is" without express or implied warranty. * * * *****************************************************************************/ #include #include #include #include #include /* Exported to machdep.c. */ struct callout *callfree, *callout; static struct callout calltodo; 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 clock, running hz times per second, is used to keep * track of real time. 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.) */ /* * TODO: * allocate more timeout table slots when table overflows. */ /* * Bump a timeval by a small number of usec's. */ #define BUMPTIME(t, usec) { \ register volatile struct timeval *tp = (t); \ register long us; \ \ tp->tv_usec = us = tp->tv_usec + (usec); \ if (us >= 1000000) { \ tp->tv_usec = us - 1000000; \ tp->tv_sec++; \ } \ } int ticks; volatile struct timeval time; volatile struct timeval mono_time; /* * The real-time timer, interrupting hz times per second. */ void bsd_hardclock(void) { register struct callout *p1; register int needsoft; unsigned cpl; int s; save_cpl(&cpl); splhigh(); /* * Update real-time timeout queue. * At front of queue are some number of events which are ``due''. * The time to these is <= 0 and if negative represents the * number of ticks which have passed since it was supposed to happen. * The rest of the q elements (times > 0) are events yet to happen, * where the time for each is given as a delta from the previous. * Decrementing just the first of these serves to decrement the time * to all events. */ needsoft = 0; for (p1 = calltodo.c_next; p1 != NULL; p1 = p1->c_next) { if (--p1->c_time > 0) break; needsoft = 1; if (p1->c_time == 0) break; } /* * Increment the time-of-day. */ ticks++; BUMPTIME(&mono_time, tick); BUMPTIME(&time, tick); /* * At this point, we might need a soft interrupt. We say, what the * heck, let's do the work now. Reduce priority level to softclock * first, though. The alternative (postponing it) would be called * 'setsoftclock' */ if (needsoft) { (void)splsoftclock(); softclock(); } restore_cpl(cpl); } /* * Software (low priority) clock interrupt. * Run periodic events from timeout queue. */ /*ARGSUSED*/ void softclock() { register struct callout *c; register void *arg; register void (*func) __P((void *)); register int s; s = splhigh(); while ((c = calltodo.c_next) != NULL && c->c_time <= 0) { func = c->c_func; arg = c->c_arg; calltodo.c_next = c->c_next; c->c_next = callfree; callfree = c; splx(s); (*func)(arg); (void) splhigh(); } splx(s); } /* * timeout -- * Execute a function after a specified length of time. * * untimeout -- * Cancel previous timeout function call. * * See AT&T BCI Driver Reference Manual for specification. This * implementation differs from that one in that no identification * value is returned from timeout, rather, the original arguments * to timeout are used to identify entries for untimeout. */ void timeout(ftn, arg, ticks) timeout_t ftn; void *arg; register int ticks; { register struct callout *new, *p, *t; register int s; if (ticks <= 0) ticks = 1; /* Lock out the clock. */ s = splhigh(); /* Fill in the next free callout structure. */ if (callfree == NULL) panic("timeout table full"); new = callfree; callfree = new->c_next; new->c_arg = arg; new->c_func = ftn; /* * The time for each event is stored as a difference from the time * of the previous event on the queue. Walk the queue, correcting * the ticks argument for queue entries passed. Correct the ticks * value for the queue entry immediately after the insertion point * as well. Watch out for negative c_time values; these represent * overdue events. */ for (p = &calltodo; (t = p->c_next) != NULL && ticks > t->c_time; p = t) if (t->c_time > 0) ticks -= t->c_time; new->c_time = ticks; if (t != NULL) t->c_time -= ticks; /* Insert the new entry into the queue. */ p->c_next = new; new->c_next = t; splx(s); } void untimeout(ftn, arg) timeout_t ftn; void *arg; { register struct callout *p, *t; register int s; s = splhigh(); for (p = &calltodo; (t = p->c_next) != NULL; p = t) if (t->c_func == ftn && t->c_arg == arg) { /* Increment next entry's tick count. */ if (t->c_next && t->c_time > 0) t->c_next->c_time += t->c_time; /* Move entry from callout queue to callfree queue. */ p->c_next = t->c_next; t->c_next = callfree; callfree = t; break; } splx(s); } /* * Compute number of hz until specified time. Used to * compute third argument to timeout() from an absolute time. */ int hzto(tv) struct timeval *tv; { register unsigned long ticks; register long sec, usec; int s; /* * 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. */ s = splclock(); sec = tv->tv_sec - time.tv_sec; usec = tv->tv_usec - time.tv_usec; splx(s); if (usec < 0) { sec--; usec += 1000000; } if (sec < 0) { #ifdef DIAGNOSTIC printf("hzto: 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 (ticks); }