block/accounting.c

   1 /*
   2  * QEMU System Emulator block accounting
   3  *
   4  * Copyright (c) 2011 Christoph Hellwig
   5  * Copyright (c) 2015 Igalia, S.L.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "qemu/osdep.h"
  27 #include "block/accounting.h"
  28 #include "block/block_int.h"
  29 #include "qemu/timer.h"
  30 #include "sysemu/qtest.h"
  31
  32 static QEMUClockType clock_type = QEMU_CLOCK_REALTIME;
  33 static const int qtest_latency_ns = NANOSECONDS_PER_SECOND / 1000;
  34
  35 void block_acct_init(BlockAcctStats *stats)
  36 {
  37     qemu_mutex_init(&stats->lock);
  38     if (qtest_enabled()) {
  39         clock_type = QEMU_CLOCK_VIRTUAL;
  40     }
  41 }
  42
  43 void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
  44                       bool account_failed)
  45 {
  46     stats->account_invalid = account_invalid;
  47     stats->account_failed = account_failed;
  48 }
  49
  50 void block_acct_cleanup(BlockAcctStats *stats)
  51 {
  52     BlockAcctTimedStats *s, *next;
  53     QSLIST_FOREACH_SAFE(s, &stats->intervals, entries, next) {
  54         g_free(s);
  55     }
  56     qemu_mutex_destroy(&stats->lock);
  57 }
  58
  59 void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length)
  60 {
  61     BlockAcctTimedStats *s;
  62     unsigned i;
  63
  64     s = g_new0(BlockAcctTimedStats, 1);
  65     s->interval_length = interval_length;
  66     s->stats = stats;
  67     qemu_mutex_lock(&stats->lock);
  68     QSLIST_INSERT_HEAD(&stats->intervals, s, entries);
  69
  70     for (i = 0; i < BLOCK_MAX_IOTYPE; i++) {
  71         timed_average_init(&s->latency[i], clock_type,
  72                            (uint64_t) interval_length * NANOSECONDS_PER_SECOND);
  73     }
  74     qemu_mutex_unlock(&stats->lock);
  75 }
  76
  77 BlockAcctTimedStats *block_acct_interval_next(BlockAcctStats *stats,
  78                                               BlockAcctTimedStats *s)
  79 {
  80     if (s == NULL) {
  81         return QSLIST_FIRST(&stats->intervals);
  82     } else {
  83         return QSLIST_NEXT(s, entries);
  84     }
  85 }
  86
  87 void block_acct_start(BlockAcctStats *stats, BlockAcctCookie *cookie,
  88                       int64_t bytes, enum BlockAcctType type)
  89 {
  90     assert(type < BLOCK_MAX_IOTYPE);
  91
  92     cookie->bytes = bytes;
  93     cookie->start_time_ns = qemu_clock_get_ns(clock_type);
  94     cookie->type = type;
  95 }
  96
  97 /* block_latency_histogram_compare_func:
  98  * Compare @key with interval [@it[0], @it[1]).
  99  * Return: -1 if @key < @it[0]
 100  *          0 if @key in [@it[0], @it[1])
 101  *         +1 if @key >= @it[1]
 102  */
 103 static int block_latency_histogram_compare_func(const void *key, const void *it)
 104 {
 105     uint64_t k = *(uint64_t *)key;
 106     uint64_t a = ((uint64_t *)it)[0];
 107     uint64_t b = ((uint64_t *)it)[1];
 108
 109     return k < a ? -1 : (k < b ? 0 : 1);
 110 }
 111
 112 static void block_latency_histogram_account(BlockLatencyHistogram *hist,
 113                                             int64_t latency_ns)
 114 {
 115     uint64_t *pos;
 116
 117     if (hist->bins == NULL) {
 118         /* histogram disabled */
 119         return;
 120     }
 121
 122
 123     if (latency_ns < hist->boundaries[0]) {
 124         hist->bins[0]++;
 125         return;
 126     }
 127
 128     if (latency_ns >= hist->boundaries[hist->nbins - 2]) {
 129         hist->bins[hist->nbins - 1]++;
 130         return;
 131     }
 132
 133     pos = bsearch(&latency_ns, hist->boundaries, hist->nbins - 2,
 134                   sizeof(hist->boundaries[0]),
 135                   block_latency_histogram_compare_func);
 136     assert(pos != NULL);
 137
 138     hist->bins[pos - hist->boundaries + 1]++;
 139 }
 140
 141 int block_latency_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
 142                                 uint64List *boundaries)
 143 {
 144     BlockLatencyHistogram *hist = &stats->latency_histogram[type];
 145     uint64List *entry;
 146     uint64_t *ptr;
 147     uint64_t prev = 0;
 148     int new_nbins = 1;
 149
 150     for (entry = boundaries; entry; entry = entry->next) {
 151         if (entry->value <= prev) {
 152             return -EINVAL;
 153         }
 154         new_nbins++;
 155         prev = entry->value;
 156     }
 157
 158     hist->nbins = new_nbins;
 159     g_free(hist->boundaries);
 160     hist->boundaries = g_new(uint64_t, hist->nbins - 1);
 161     for (entry = boundaries, ptr = hist->boundaries; entry;
 162          entry = entry->next, ptr++)
 163     {
 164         *ptr = entry->value;
 165     }
 166
 167     g_free(hist->bins);
 168     hist->bins = g_new0(uint64_t, hist->nbins);
 169
 170     return 0;
 171 }
 172
 173 void block_latency_histograms_clear(BlockAcctStats *stats)
 174 {
 175     int i;
 176
 177     for (i = 0; i < BLOCK_MAX_IOTYPE; i++) {
 178         BlockLatencyHistogram *hist = &stats->latency_histogram[i];
 179         g_free(hist->bins);
 180         g_free(hist->boundaries);
 181         memset(hist, 0, sizeof(*hist));
 182     }
 183 }
 184
 185 static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie,
 186                                  bool failed)
 187 {
 188     BlockAcctTimedStats *s;
 189     int64_t time_ns = qemu_clock_get_ns(clock_type);
 190     int64_t latency_ns = time_ns - cookie->start_time_ns;
 191
 192     if (qtest_enabled()) {
 193         latency_ns = qtest_latency_ns;
 194     }
 195
 196     assert(cookie->type < BLOCK_MAX_IOTYPE);
 197
 198     if (cookie->type == BLOCK_ACCT_NONE) {
 199         return;
 200     }
 201
 202     WITH_QEMU_LOCK_GUARD(&stats->lock) {
 203         if (failed) {
 204             stats->failed_ops[cookie->type]++;
 205         } else {
 206             stats->nr_bytes[cookie->type] += cookie->bytes;
 207             stats->nr_ops[cookie->type]++;
 208         }
 209
 210         block_latency_histogram_account(&stats->latency_histogram[cookie->type],
 211                                         latency_ns);
 212
 213         if (!failed || stats->account_failed) {
 214             stats->total_time_ns[cookie->type] += latency_ns;
 215             stats->last_access_time_ns = time_ns;
 216
 217             QSLIST_FOREACH(s, &stats->intervals, entries) {
 218                 timed_average_account(&s->latency[cookie->type], latency_ns);
 219             }
 220         }
 221     }
 222
 223     cookie->type = BLOCK_ACCT_NONE;
 224 }
 225
 226 void block_acct_done(BlockAcctStats *stats, BlockAcctCookie *cookie)
 227 {
 228     block_account_one_io(stats, cookie, false);
 229 }
 230
 231 void block_acct_failed(BlockAcctStats *stats, BlockAcctCookie *cookie)
 232 {
 233     block_account_one_io(stats, cookie, true);
 234 }
 235
 236 void block_acct_invalid(BlockAcctStats *stats, enum BlockAcctType type)
 237 {
 238     assert(type < BLOCK_MAX_IOTYPE);
 239
 240     /* block_account_one_io() updates total_time_ns[], but this one does
 241      * not.  The reason is that invalid requests are accounted during their
 242      * submission, therefore there's no actual I/O involved.
 243      */
 244     qemu_mutex_lock(&stats->lock);
 245     stats->invalid_ops[type]++;
 246
 247     if (stats->account_invalid) {
 248         stats->last_access_time_ns = qemu_clock_get_ns(clock_type);
 249     }
 250     qemu_mutex_unlock(&stats->lock);
 251 }
 252
 253 void block_acct_merge_done(BlockAcctStats *stats, enum BlockAcctType type,
 254                       int num_requests)
 255 {
 256     assert(type < BLOCK_MAX_IOTYPE);
 257
 258     qemu_mutex_lock(&stats->lock);
 259     stats->merged[type] += num_requests;
 260     qemu_mutex_unlock(&stats->lock);
 261 }
 262
 263 int64_t block_acct_idle_time_ns(BlockAcctStats *stats)
 264 {
 265     return qemu_clock_get_ns(clock_type) - stats->last_access_time_ns;
 266 }
 267
 268 double block_acct_queue_depth(BlockAcctTimedStats *stats,
 269                               enum BlockAcctType type)
 270 {
 271     uint64_t sum, elapsed;
 272
 273     assert(type < BLOCK_MAX_IOTYPE);
 274
 275     qemu_mutex_lock(&stats->stats->lock);
 276     sum = timed_average_sum(&stats->latency[type], &elapsed);
 277     qemu_mutex_unlock(&stats->stats->lock);
 278
 279     return (double) sum / elapsed;
 280 }