2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/kern/kern_systimer.c,v 1.5 2004/11/20 20:25:09 dillon Exp $
38 * WARNING! THE SYSTIMER MODULE DOES NOT OPERATE OR DISPATCH WITH THE
39 * MP LOCK HELD. ALL CODE USING THIS MODULE MUST BE MP-SAFE.
41 * This code implements a fine-grained per-cpu system timer which is
42 * ultimately based on a hardware timer. The hardware timer abstraction
43 * is sufficiently disconnected from this code to support both per-cpu
44 * hardware timers or a single system-wide hardware timer.
46 * Notes on machine-dependant code (in arch/arch/systimer.c)
48 * cputimer_intr_reload() Reload the one-shot (per-cpu basis)
50 * cputimer_count() Get the current absolute sysclock_t value.
53 #include <sys/param.h>
54 #include <sys/kernel.h>
55 #include <sys/systm.h>
56 #include <sys/thread.h>
57 #include <sys/globaldata.h>
58 #include <sys/systimer.h>
59 #include <sys/thread2.h>
62 * Execute ready systimers. Called directly from the platform-specific
63 * one-shot timer clock interrupt (e.g. clkintr()). Systimer functions are
64 * responsible for calling hardclock, statclock, and other finely-timed
68 systimer_intr(sysclock_t *timep, struct intrframe *frame)
70 globaldata_t gd = mycpu;
71 sysclock_t time = *timep;
79 while ((info = TAILQ_FIRST(&gd->gd_systimerq)) != NULL) {
81 * If we haven't reached the requested time, tell the cputimer
82 * how much is left and break out.
84 if ((int)(info->time - time) > 0) {
85 cputimer_intr_reload(info->time - time);
92 info->flags &= ~SYSTF_ONQUEUE;
93 TAILQ_REMOVE(info->queue, info, node);
95 info->func(info, frame);
99 * Reinstall if periodic. If this is a non-queued periodic
100 * interrupt do not allow multiple events to build up (used
101 * for things like the callout timer to prevent premature timeouts
102 * due to long interrupt disablements, BIOS 8254 glitching, and so
103 * forth). However, we still want to keep things synchronized between
104 * cpus for efficient handling of the timer interrupt so jump in
105 * multiples of the periodic rate.
107 if (info->periodic) {
108 info->time += info->periodic;
109 if ((info->flags & SYSTF_NONQUEUED) &&
110 (int)(info->time - time) <= 0
112 info->time += ((time - info->time + info->periodic - 1) /
113 info->periodic) * info->periodic;
119 gd->gd_nextclock = info->time;
121 gd->gd_nextclock = 0;
127 systimer_add(systimer_t info)
129 struct globaldata *gd = mycpu;
131 KKASSERT((info->flags & (SYSTF_ONQUEUE|SYSTF_IPIRUNNING)) == 0);
133 if (info->gd == gd) {
136 scan1 = TAILQ_FIRST(&gd->gd_systimerq);
137 if (scan1 == NULL || (int)(scan1->time - info->time) > 0) {
138 gd->gd_nextclock = info->time;
139 cputimer_intr_reload(info->time - cputimer_count());
140 TAILQ_INSERT_HEAD(&gd->gd_systimerq, info, node);
142 scan2 = TAILQ_LAST(&gd->gd_systimerq, systimerq);
145 TAILQ_INSERT_TAIL(&gd->gd_systimerq, info, node);
148 if ((int)(scan1->time - info->time) > 0) {
149 TAILQ_INSERT_BEFORE(scan1, info, node);
152 if ((int)(scan2->time - info->time) <= 0) {
153 TAILQ_INSERT_AFTER(&gd->gd_systimerq, scan2, info, node);
156 scan1 = TAILQ_NEXT(scan1, node);
157 scan2 = TAILQ_PREV(scan2, systimerq, node);
160 info->flags = (info->flags | SYSTF_ONQUEUE) & ~SYSTF_IPIRUNNING;
161 info->queue = &gd->gd_systimerq;
163 info->flags |= SYSTF_IPIRUNNING;
164 lwkt_send_ipiq(info->gd, (ipifunc_t)systimer_add, info);
172 * Delete a system timer. Only the owning cpu can delete a timer.
175 systimer_del(systimer_t info)
177 KKASSERT(info->gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0);
179 if (info->flags & SYSTF_ONQUEUE) {
180 TAILQ_REMOVE(info->queue, info, node);
181 info->flags &= ~SYSTF_ONQUEUE;
187 * systimer_init_periodic()
189 * Initialize a periodic timer at the specified frequency and add
190 * it to the system. The frequency is uncompensated and approximate.
192 * Try to synchronize multi registrations of the same or similar
193 * frequencies so the hardware interrupt is able to dispatch several
194 * at together by adjusting the phase of the initial interrupt. This
195 * helps SMP. Note that we are not attempting to synchronize to
196 * the realtime clock.
199 systimer_init_periodic(systimer_t info, void *func, void *data, int hz)
201 sysclock_t base_count;
203 bzero(info, sizeof(struct systimer));
204 info->periodic = cputimer_fromhz(hz);
205 base_count = cputimer_count();
206 base_count = base_count - (base_count % info->periodic);
207 info->time = base_count + info->periodic;
215 systimer_init_periodic_nq(systimer_t info, void *func, void *data, int hz)
217 sysclock_t base_count;
219 bzero(info, sizeof(struct systimer));
220 info->periodic = cputimer_fromhz(hz);
221 base_count = cputimer_count();
222 base_count = base_count - (base_count % info->periodic);
223 info->time = base_count + info->periodic;
227 info->flags |= SYSTF_NONQUEUED;
232 * systimer_init_oneshot()
234 * Initialize a periodic timer at the specified frequency and add
235 * it to the system. The frequency is uncompensated and approximate.
238 systimer_init_oneshot(systimer_t info, void *func, void *data, int us)
240 bzero(info, sizeof(struct systimer));
241 info->time = cputimer_count() + cputimer_fromus(us);