2 * Copyright (c) 2005 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;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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_cputimer.c,v 1.1 2005/06/01 20:19:47 dillon Exp $
37 * Generic cputimer - access to a reliable, free-running counter.
40 #include <sys/param.h>
41 #include <sys/kernel.h>
42 #include <sys/systm.h>
43 #include <sys/thread.h>
44 #include <sys/globaldata.h>
45 #include <sys/systimer.h>
46 #include <sys/sysctl.h>
47 #include <sys/thread2.h>
49 static sysclock_t dummy_cputimer_count(void);
51 static struct cputimer dummy_cputimer = {
57 cputimer_default_fromhz,
58 cputimer_default_fromus,
59 cputimer_default_construct,
60 cputimer_default_destruct,
62 (1000000LL << 32) / 1000000,
63 (1000000000LL << 32) / 1000000,
67 static struct cputimer *cputimer_reg_base = &dummy_cputimer;
68 struct cputimer *sys_cputimer = &dummy_cputimer;
71 * Generic cputimer API
74 cputimer_select(struct cputimer *timer, int pri)
79 * Calculate helper fields
81 cputimer_set_frequency(timer, timer->freq);
84 * Install a new cputimer if its priority allows it. If timer is
85 * passed as NULL we deinstall the current timer and revert to our
90 if (timer == NULL || pri >= sys_cputimer->pri) {
91 oldclock = sys_cputimer->count();
92 sys_cputimer->destruct(sys_cputimer);
93 sys_cputimer = &dummy_cputimer;
96 timer->construct(timer, oldclock);
102 * Register a timer. If the timer has already been registered, do nothing.
105 cputimer_register(struct cputimer *timer)
107 struct cputimer **scanpp;
108 struct cputimer *scan;
110 for (scanpp = &cputimer_reg_base;
111 (scan = *scanpp) != NULL;
122 * Deregister a timer. If the timer has already been deregistered, do nothing.
125 cputimer_deregister(struct cputimer *timer)
127 struct cputimer **scanpp;
128 struct cputimer *scan;
129 struct cputimer *best;
132 * Locate and remove the timer. If the timer is our currently active
133 * timer, revert to the dummy timer.
135 scanpp = &cputimer_reg_base;
136 while ((scan = *scanpp) != NULL) {
138 *scanpp = timer->next;
139 if (timer == sys_cputimer)
140 cputimer_select(&dummy_cputimer, 0x7FFFFFFF);
142 scanpp = &scan->next;
147 * If sys_cputimer reverted to the dummy, select the best one
149 if (sys_cputimer == &dummy_cputimer) {
151 for (scan = cputimer_reg_base; scan; scan = scan->next) {
152 if (best == NULL || scan->pri > best->pri)
156 cputimer_select(best, 0x7FFFFFFF);
161 * Calculate usec / tick and nsec / tick, scaled by (1 << 32).
163 * so e.g. a 3 mhz timer would be 3 usec / tick x (1 << 32),
164 * or 3000 nsec / tick x (1 << 32)
167 cputimer_set_frequency(struct cputimer *timer, int freq)
170 timer->freq64_usec = (1000000LL << 32) / freq;
171 timer->freq64_nsec = (1000000000LL << 32) / freq;
175 cputimer_default_fromhz(int freq)
177 return(sys_cputimer->freq / freq + 1);
181 cputimer_default_fromus(int us)
183 return((int64_t)sys_cputimer->freq * us / 1000000);
187 * Dummy counter implementation
191 dummy_cputimer_count(void)
193 return(++dummy_cputimer.base);
197 cputimer_default_construct(struct cputimer *cputimer, sysclock_t oldclock)
199 cputimer->base = oldclock;
203 cputimer_default_destruct(struct cputimer *cputimer)
207 /************************************************************************
209 ************************************************************************/
212 sysctl_cputimer_reglist(SYSCTL_HANDLER_ARGS)
214 struct cputimer *scan;
215 struct cputimer *selected;
221 * Writing to the reglist selects a timer
223 if (req->newptr != NULL) {
224 if (req->newlen < 0 || req->newlen >= sizeof(buf))
225 return (ENAMETOOLONG);
226 error = SYSCTL_IN(req, buf, req->newlen);
227 buf[req->newlen] = 0;
233 * Build a list of available timers
236 for (scan = cputimer_reg_base; scan; scan = scan->next) {
237 if (error == 0 && loop)
238 error = SYSCTL_OUT(req, " ", 1);
240 error = SYSCTL_OUT(req, scan->name, strlen(scan->name));
241 if (buf[0] && strcmp(buf, scan->name) == 0)
247 * If a particular timer is being selected by the sysctl, switch to it.
250 cputimer_select(selected, 0x7FFFFFFF);
251 if (error == 0 && buf[0] && selected == NULL)
257 sysctl_cputimer_name(SYSCTL_HANDLER_ARGS)
261 error = SYSCTL_OUT(req, sys_cputimer->name, strlen(sys_cputimer->name));
266 sysctl_cputimer_clock(SYSCTL_HANDLER_ARGS)
271 clock = sys_cputimer->count();
272 error = SYSCTL_OUT(req, &clock, sizeof(clock));
277 sysctl_cputimer_freq(SYSCTL_HANDLER_ARGS)
281 error = SYSCTL_OUT(req, &sys_cputimer->freq, sizeof(sys_cputimer->freq));
285 SYSCTL_DECL(_kern_cputimer);
286 SYSCTL_NODE(_kern, OID_AUTO, cputimer, CTLFLAG_RW, NULL, "cputimer");
288 SYSCTL_PROC(_kern_cputimer, OID_AUTO, select, CTLTYPE_STRING|CTLFLAG_RW,
289 NULL, NULL, sysctl_cputimer_reglist, "A", "");
290 SYSCTL_PROC(_kern_cputimer, OID_AUTO, name, CTLTYPE_STRING|CTLFLAG_RD,
291 NULL, NULL, sysctl_cputimer_name, "A", "");
292 SYSCTL_PROC(_kern_cputimer, OID_AUTO, clock, CTLTYPE_UINT|CTLFLAG_RD,
293 NULL, NULL, sysctl_cputimer_clock, "IU", "");
294 SYSCTL_PROC(_kern_cputimer, OID_AUTO, freq, CTLTYPE_INT|CTLFLAG_RD,
295 NULL, NULL, sysctl_cputimer_freq, "I", "");