1 /* 2 * Copyright (c) 2005 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 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 16 * distribution. 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. 20 * 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 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sys/kern/kern_cputimer.c,v 1.5 2008/06/05 18:06:32 swildner Exp $ 35 */ 36 /* 37 * Generic cputimer - access to a reliable, free-running counter. 38 */ 39 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> 48 49 static sysclock_t dummy_cputimer_count(void); 50 51 static struct cputimer dummy_cputimer = { 52 SLIST_ENTRY_INITIALIZER, 53 "dummy", 54 CPUTIMER_PRI_DUMMY, 55 CPUTIMER_DUMMY, 56 dummy_cputimer_count, 57 cputimer_default_fromhz, 58 cputimer_default_fromus, 59 cputimer_default_construct, 60 cputimer_default_destruct, 61 1000000, 62 (1000000LL << 32) / 1000000, 63 (1000000000LL << 32) / 1000000, 64 0 65 }; 66 67 struct cputimer *sys_cputimer = &dummy_cputimer; 68 SLIST_HEAD(, cputimer) cputimerhead = SLIST_HEAD_INITIALIZER(&cputimerhead); 69 70 /* 71 * Generic cputimer API 72 */ 73 void 74 cputimer_select(struct cputimer *timer, int pri) 75 { 76 sysclock_t oldclock; 77 78 /* 79 * Calculate helper fields 80 */ 81 cputimer_set_frequency(timer, timer->freq); 82 83 /* 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 86 * dummy. 87 */ 88 if (pri == 0) 89 pri = timer->pri; 90 if (timer == NULL || pri >= sys_cputimer->pri) { 91 oldclock = sys_cputimer->count(); 92 sys_cputimer->destruct(sys_cputimer); 93 sys_cputimer = &dummy_cputimer; 94 if (timer) { 95 sys_cputimer = timer; 96 timer->construct(timer, oldclock); 97 cputimer_intr_config(timer); 98 } 99 } 100 } 101 102 /* 103 * Register a timer. If the timer has already been registered, do nothing. 104 */ 105 void 106 cputimer_register(struct cputimer *timer) 107 { 108 struct cputimer *scan; 109 110 /* 111 * Initialize dummy_cputimer if the slist is empty, it does not get 112 * registered the normal way. 113 */ 114 if (SLIST_EMPTY(&cputimerhead)) 115 SLIST_FIRST(&cputimerhead) = &dummy_cputimer; 116 SLIST_FOREACH(scan, &cputimerhead, next) { 117 if (scan == timer) 118 return; 119 } 120 SLIST_INSERT_HEAD(&cputimerhead, timer, next); 121 } 122 123 /* 124 * Deregister a timer. If the timer has already been deregistered, do nothing. 125 */ 126 void 127 cputimer_deregister(struct cputimer *timer) 128 { 129 struct cputimer *scan; 130 struct cputimer *best; 131 132 /* 133 * Locate and remove the timer. If the timer is our currently active 134 * timer, revert to the dummy timer. 135 */ 136 SLIST_FOREACH(scan, &cputimerhead, next) { 137 if (timer == scan) { 138 if (timer == sys_cputimer) 139 cputimer_select(&dummy_cputimer, 0x7FFFFFFF); 140 SLIST_REMOVE(&cputimerhead, timer, cputimer, next); 141 break; 142 } 143 } 144 145 /* 146 * If sys_cputimer reverted to the dummy, select the best one 147 */ 148 if (sys_cputimer == &dummy_cputimer) { 149 best = NULL; 150 SLIST_FOREACH(scan, &cputimerhead, next) { 151 if (best == NULL || scan->pri > best->pri) 152 best = scan; 153 } 154 if (best) 155 cputimer_select(best, 0x7FFFFFFF); 156 } 157 } 158 159 /* 160 * Calculate usec / tick and nsec / tick, scaled by (1 << 32). 161 * 162 * so e.g. a 3 mhz timer would be 3 usec / tick x (1 << 32), 163 * or 3000 nsec / tick x (1 << 32) 164 */ 165 void 166 cputimer_set_frequency(struct cputimer *timer, int freq) 167 { 168 timer->freq = freq; 169 timer->freq64_usec = (1000000LL << 32) / freq; 170 timer->freq64_nsec = (1000000000LL << 32) / freq; 171 if (timer == sys_cputimer) 172 cputimer_intr_config(timer); 173 } 174 175 sysclock_t 176 cputimer_default_fromhz(int freq) 177 { 178 return(sys_cputimer->freq / freq + 1); 179 } 180 181 sysclock_t 182 cputimer_default_fromus(int us) 183 { 184 return((int64_t)sys_cputimer->freq * us / 1000000); 185 } 186 187 /* 188 * Dummy counter implementation 189 */ 190 static 191 sysclock_t 192 dummy_cputimer_count(void) 193 { 194 return(++dummy_cputimer.base); 195 } 196 197 void 198 cputimer_default_construct(struct cputimer *cputimer, sysclock_t oldclock) 199 { 200 cputimer->base = oldclock; 201 } 202 203 void 204 cputimer_default_destruct(struct cputimer *cputimer) 205 { 206 } 207 208 /************************************************************************ 209 * SYSCTL SUPPORT * 210 ************************************************************************ 211 * 212 * Note: the ability to change the systimer is not currently enabled 213 * because it will mess up systimer calculations. You have to live 214 * with what is configured at boot. 215 */ 216 static int 217 sysctl_cputimer_reglist(SYSCTL_HANDLER_ARGS) 218 { 219 struct cputimer *scan; 220 int error = 0; 221 int loop = 0; 222 223 /* 224 * Build a list of available timers 225 */ 226 SLIST_FOREACH(scan, &cputimerhead, next) { 227 if (error == 0 && loop) 228 error = SYSCTL_OUT(req, " ", 1); 229 if (error == 0) 230 error = SYSCTL_OUT(req, scan->name, strlen(scan->name)); 231 ++loop; 232 } 233 return (error); 234 } 235 236 static int 237 sysctl_cputimer_name(SYSCTL_HANDLER_ARGS) 238 { 239 int error; 240 241 error = SYSCTL_OUT(req, sys_cputimer->name, strlen(sys_cputimer->name)); 242 return (error); 243 } 244 245 static int 246 sysctl_cputimer_clock(SYSCTL_HANDLER_ARGS) 247 { 248 sysclock_t clock; 249 int error; 250 251 clock = sys_cputimer->count(); 252 error = SYSCTL_OUT(req, &clock, sizeof(clock)); 253 return (error); 254 } 255 256 static int 257 sysctl_cputimer_freq(SYSCTL_HANDLER_ARGS) 258 { 259 int error; 260 261 error = SYSCTL_OUT(req, &sys_cputimer->freq, sizeof(sys_cputimer->freq)); 262 return (error); 263 } 264 265 SYSCTL_DECL(_kern_cputimer); 266 SYSCTL_NODE(_kern, OID_AUTO, cputimer, CTLFLAG_RW, NULL, "cputimer"); 267 268 SYSCTL_PROC(_kern_cputimer, OID_AUTO, select, CTLTYPE_STRING|CTLFLAG_RD, 269 NULL, 0, sysctl_cputimer_reglist, "A", ""); 270 SYSCTL_PROC(_kern_cputimer, OID_AUTO, name, CTLTYPE_STRING|CTLFLAG_RD, 271 NULL, 0, sysctl_cputimer_name, "A", ""); 272 SYSCTL_PROC(_kern_cputimer, OID_AUTO, clock, CTLTYPE_UINT|CTLFLAG_RD, 273 NULL, 0, sysctl_cputimer_clock, "IU", ""); 274 SYSCTL_PROC(_kern_cputimer, OID_AUTO, freq, CTLTYPE_INT|CTLFLAG_RD, 275 NULL, 0, sysctl_cputimer_freq, "I", ""); 276 277 278