subr_devstat.c revision 39985
1/* 2 * Copyright (c) 1997, 1998 Kenneth D. Merry. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $Id: subr_devstat.c,v 1.2 1998/09/20 00:10:39 ken Exp $ 29 */ 30 31#include <sys/param.h> 32#include <sys/kernel.h> 33#include <sys/systm.h> 34#include <sys/time.h> 35#include <sys/types.h> 36#include <sys/sysctl.h> 37 38#include <sys/devicestat.h> 39 40static int devstat_num_devs; 41static long devstat_generation; 42static int devstat_version = DEVSTAT_VERSION; 43static int devstat_current_devnumber; 44 45STAILQ_HEAD(devstatlist, devstat) device_statq; 46 47/* 48 * Take a malloced and zeroed devstat structure given to us, fill it in 49 * and add it to the queue of devices. 50 */ 51void 52devstat_add_entry(struct devstat *ds, char *dev_name, 53 int unit_number, u_int32_t block_size, 54 devstat_support_flags flags, 55 devstat_type_flags device_type) 56{ 57 int s; 58 struct devstatlist *devstat_head; 59 60 if (ds == NULL) 61 return; 62 63 if (devstat_num_devs == 0) 64 STAILQ_INIT(&device_statq); 65 66 devstat_generation++; 67 devstat_num_devs++; 68 69 devstat_head = &device_statq; 70 71 STAILQ_INSERT_TAIL(devstat_head, ds, dev_links); 72 73 ds->device_number = devstat_current_devnumber++; 74 ds->unit_number = unit_number; 75 strncpy(ds->device_name, dev_name, DEVSTAT_NAME_LEN); 76 ds->block_size = block_size; 77 ds->flags = flags; 78 ds->device_type = device_type; 79 80 s = splclock(); 81 getmicrotime(&ds->dev_creation_time); 82 splx(s); 83} 84 85/* 86 * Remove a devstat structure from the list of devices. 87 */ 88void 89devstat_remove_entry(struct devstat *ds) 90{ 91 struct devstatlist *devstat_head; 92 93 if (ds == NULL) 94 return; 95 96 devstat_generation++; 97 devstat_num_devs--; 98 99 devstat_head = &device_statq; 100 101 /* Remove this entry from the devstat queue */ 102 STAILQ_REMOVE(devstat_head, ds, devstat, dev_links); 103} 104 105/* 106 * Record a transaction start. 107 */ 108void 109devstat_start_transaction(struct devstat *ds) 110{ 111 int s; 112 113 /* sanity check */ 114 if (ds == NULL) 115 return; 116 117 /* 118 * We only want to set the start time when we are going from idle 119 * to busy. The start time is really the start of the latest busy 120 * period. 121 */ 122 if (ds->busy_count == 0) { 123 s = splclock(); 124 getmicrouptime(&ds->start_time); 125 splx(s); 126 } 127 ds->busy_count++; 128} 129 130/* 131 * Record the ending of a transaction, and incrment the various counters. 132 */ 133void 134devstat_end_transaction(struct devstat *ds, u_int32_t bytes, 135 devstat_tag_type tag_type, devstat_trans_flags flags) 136{ 137 int s; 138 struct timeval busy_time; 139 140 /* sanity check */ 141 if (ds == NULL) 142 return; 143 144 s = splclock(); 145 getmicrouptime(&ds->last_comp_time); 146 splx(s); 147 148 ds->busy_count--; 149 150 /* 151 * There might be some transactions (DEVSTAT_NO_DATA) that don't 152 * transfer any data. 153 */ 154 if (flags == DEVSTAT_READ) { 155 ds->bytes_read += bytes; 156 ds->num_reads++; 157 } else if (flags == DEVSTAT_WRITE) { 158 ds->bytes_written += bytes; 159 ds->num_writes++; 160 } else 161 ds->num_other++; 162 163 /* 164 * Keep a count of the various tag types sent. 165 */ 166 if (tag_type != DEVSTAT_TAG_NONE) 167 ds->tag_types[tag_type]++; 168 169 /* 170 * We only update the busy time when we go idle. Otherwise, this 171 * calculation would require many more clock cycles. 172 */ 173 if (ds->busy_count == 0) { 174 /* Calculate how long we were busy */ 175 busy_time = ds->last_comp_time; 176 timevalsub(&busy_time, &ds->start_time); 177 178 /* Add our busy time to the total busy time. */ 179 timevaladd(&ds->busy_time, &busy_time); 180 } else if (ds->busy_count < 0) 181 printf("devstat_end_transaction: HELP!! busy_count " 182 "for %s%d is < 0 (%d)!\n", ds->device_name, 183 ds->unit_number, ds->busy_count); 184} 185 186/* 187 * This is the sysctl handler for the devstat package. The data pushed out 188 * on the kern.devstat.all sysctl variable consists of the current devstat 189 * generation number, and then an array of devstat structures, one for each 190 * device in the system. 191 * 192 * I'm really not too fond of this method of doing things, but there really 193 * aren't that many alternatives. We must have some method of making sure 194 * that the generation number the user gets corresponds with the data the 195 * user gets. If the user makes a separate sysctl call to get the 196 * generation, and then a sysctl call to get the device statistics, the 197 * device list could have changed in that brief period of time. By 198 * supplying the generation number along with the statistics output, we can 199 * guarantee that the generation number and the statistics match up. 200 */ 201static int 202sysctl_devstat SYSCTL_HANDLER_ARGS 203{ 204 int error, i; 205 struct devstat *nds; 206 struct devstatlist *devstat_head; 207 208 if (devstat_num_devs == 0) 209 return(EINVAL); 210 211 error = 0; 212 devstat_head = &device_statq; 213 214 /* 215 * First push out the generation number. 216 */ 217 error = SYSCTL_OUT(req, &devstat_generation, sizeof(long)); 218 219 /* 220 * Now push out all the devices. 221 */ 222 for (i = 0, nds = devstat_head->stqh_first; 223 (nds != NULL) && (i < devstat_num_devs) && (error == 0); 224 nds = nds->dev_links.stqe_next, i++) 225 error = SYSCTL_OUT(req, nds, sizeof(struct devstat)); 226 227 return(error); 228} 229 230/* 231 * Sysctl entries for devstat. The first one is a node that all the rest 232 * hang off of. 233 */ 234SYSCTL_NODE(_kern, OID_AUTO, devstat, CTLFLAG_RD, 0, "Device Statistics"); 235 236SYSCTL_PROC(_kern_devstat, OID_AUTO, all, CTLFLAG_RD|CTLTYPE_OPAQUE, 237 0, 0, sysctl_devstat, "S,devstat", "All Devices"); 238/* 239 * Export the number of devices in the system so that userland utilities 240 * can determine how much memory to allocate to hold all the devices. 241 */ 242SYSCTL_INT(_kern_devstat, OID_AUTO, numdevs, CTLFLAG_RD, &devstat_num_devs, 243 0, "Number of devices in the devstat list"); 244SYSCTL_LONG(_kern_devstat, OID_AUTO, generation, CTLFLAG_RD, 245 &devstat_generation, 0, "Devstat list generation"); 246SYSCTL_INT(_kern_devstat, OID_AUTO, version, CTLFLAG_RD, &devstat_version, 247 0, "Devstat list version number"); 248