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     stats->account_invalid = true;
  42     stats->account_failed = true;
  43 }
  44
  45 static bool bool_from_onoffauto(OnOffAuto val, bool def)
  46 {
  47     switch (val) {
  48     case ON_OFF_AUTO_AUTO:
  49         return def;
  50     case ON_OFF_AUTO_ON:
  51         return true;
  52     case ON_OFF_AUTO_OFF:
  53         return false;
  54     default:
  55         abort();
  56     }
  57 }
  58
  59 void block_acct_setup(BlockAcctStats *stats, enum OnOffAuto account_invalid,
  60                       enum OnOffAuto account_failed)
  61 {
  62     stats->account_invalid = bool_from_onoffauto(account_invalid,
  63                                                  stats->account_invalid);
  64     stats->account_failed = bool_from_onoffauto(account_failed,
  65                                                 stats->account_failed);
  66 }
  67
  68 void block_acct_cleanup(BlockAcctStats *stats)
  69 {
  70     BlockAcctTimedStats *s, *next;
  71     QSLIST_FOREACH_SAFE(s, &stats->intervals, entries, next) {
  72         g_free(s);
  73     }
  74     qemu_mutex_destroy(&stats->lock);
  75 }
  76
  77 void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length)
  78 {
  79     BlockAcctTimedStats *s;
  80     unsigned i;
  81
  82     s = g_new0(BlockAcctTimedStats, 1);
  83     s->interval_length = interval_length;
  84     s->stats = stats;
  85     qemu_mutex_lock(&stats->lock);
  86     QSLIST_INSERT_HEAD(&stats->intervals, s, entries);
  87
  88     for (i = 0; i < BLOCK_MAX_IOTYPE; i++) {
  89         timed_average_init(&s->latency[i], clock_type,
  90                            (uint64_t) interval_length * NANOSECONDS_PER_SECOND);
  91     }
  92     qemu_mutex_unlock(&stats->lock);
  93 }
  94
  95 BlockAcctTimedStats *block_acct_interval_next(BlockAcctStats *stats,
  96                                               BlockAcctTimedStats *s)
  97 {
  98     if (s == NULL) {
  99         return QSLIST_FIRST(&stats->intervals);
 100     } else {
 101         return QSLIST_NEXT(s, entries);
 102     }
 103 }
 104
 105 void block_acct_start(BlockAcctStats *stats, BlockAcctCookie *cookie,
 106                       int64_t bytes, enum BlockAcctType type)
 107 {
 108     assert(type < BLOCK_MAX_IOTYPE);
 109
 110     cookie->bytes = bytes;
 111     cookie->start_time_ns = qemu_clock_get_ns(clock_type);
 112     cookie->type = type;
 113 }
 114
 115 /* block_latency_histogram_compare_func:
 116  * Compare @key with interval [@it[0], @it[1]).
 117  * Return: -1 if @key < @it[0]
 118  *          0 if @key in [@it[0], @it[1])
 119  *         +1 if @key >= @it[1]
 120  */
 121 static int block_latency_histogram_compare_func(const void *key, const void *it)
 122 {
 123     uint64_t k = *(uint64_t *)key;
 124     uint64_t a = ((uint64_t *)it)[0];
 125     uint64_t b = ((uint64_t *)it)[1];
 126
 127     return k < a ? -1 : (k < b ? 0 : 1);
 128 }
 129
 130 static void block_latency_histogram_account(BlockLatencyHistogram *hist,
 131                                             int64_t latency_ns)
 132 {
 133     uint64_t *pos;
 134
 135     if (hist->bins == NULL) {
 136         /* histogram disabled */
 137         return;
 138     }
 139
 140
 141     if (latency_ns < hist->boundaries[0]) {
 142         hist->bins[0]++;
 143         return;
 144     }
 145
 146     if (latency_ns >= hist->boundaries[hist->nbins - 2]) {
 147         hist->bins[hist->nbins - 1]++;
 148         return;
 149     }
 150
 151     pos = bsearch(&latency_ns, hist->boundaries, hist->nbins - 2,
 152                   sizeof(hist->boundaries[0]),
 153                   block_latency_histogram_compare_func);
 154     assert(pos != NULL);
 155
 156     hist->bins[pos - hist->boundaries + 1]++;
 157 }
 158
 159 int block_latency_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
 160                                 uint64List *boundaries)
 161 {
 162     BlockLatencyHistogram *hist = &stats->latency_histogram[type];
 163     uint64List *entry;
 164     uint64_t *ptr;
 165     uint64_t prev = 0;
 166     int new_nbins = 1;
 167
 168     for (entry = boundaries; entry; entry = entry->next) {
 169         if (entry->value <= prev) {
 170             return -EINVAL;
 171         }
 172         new_nbins++;
 173         prev = entry->value;
 174     }
 175
 176     hist->nbins = new_nbins;
 177     g_free(hist->boundaries);
 178     hist->boundaries = g_new(uint64_t, hist->nbins - 1);
 179     for (entry = boundaries, ptr = hist->boundaries; entry;
 180          entry = entry->next, ptr++)
 181     {
 182         *ptr = entry->value;
 183     }
 184
 185     g_free(hist->bins);
 186     hist->bins = g_new0(uint64_t, hist->nbins);
 187
 188     return 0;
 189 }
 190
 191 void block_latency_histograms_clear(BlockAcctStats *stats)
 192 {
 193     int i;
 194
 195     for (i = 0; i < BLOCK_MAX_IOTYPE; i++) {
 196         BlockLatencyHistogram *hist = &stats->latency_histogram[i];
 197         g_free(hist->bins);
 198         g_free(hist->boundaries);
 199         memset(hist, 0, sizeof(*hist));
 200     }
 201 }
 202
 203 static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie,
 204                                  bool failed)
 205 {
 206     BlockAcctTimedStats *s;
 207     int64_t time_ns = qemu_clock_get_ns(clock_type);
 208     int64_t latency_ns = time_ns - cookie->start_time_ns;
 209
 210     if (qtest_enabled()) {
 211         latency_ns = qtest_latency_ns;
 212     }
 213
 214     assert(cookie->type < BLOCK_MAX_IOTYPE);
 215
 216     if (cookie->type == BLOCK_ACCT_NONE) {
 217         return;
 218     }
 219
 220     WITH_QEMU_LOCK_GUARD(&stats->lock) {
 221         if (failed) {
 222             stats->failed_ops[cookie->type]++;
 223         } else {
 224             stats->nr_bytes[cookie->type] += cookie->bytes;
 225             stats->nr_ops[cookie->type]++;
 226         }
 227
 228         block_latency_histogram_account(&stats->latency_histogram[cookie->type],
 229                                         latency_ns);
 230
 231         if (!failed || stats->account_failed) {
 232             stats->total_time_ns[cookie->type] += latency_ns;
 233             stats->last_access_time_ns = time_ns;
 234
 235             QSLIST_FOREACH(s, &stats->intervals, entries) {
 236                 timed_average_account(&s->latency[cookie->type], latency_ns);
 237             }
 238         }
 239     }
 240
 241     cookie->type = BLOCK_ACCT_NONE;
 242 }
 243
 244 void block_acct_done(BlockAcctStats *stats, BlockAcctCookie *cookie)
 245 {
 246     block_account_one_io(stats, cookie, false);
 247 }
 248
 249 void block_acct_failed(BlockAcctStats *stats, BlockAcctCookie *cookie)
 250 {
 251     block_account_one_io(stats, cookie, true);
 252 }
 253
 254 void block_acct_invalid(BlockAcctStats *stats, enum BlockAcctType type)
 255 {
 256     assert(type < BLOCK_MAX_IOTYPE);
 257
 258     /* block_account_one_io() updates total_time_ns[], but this one does
 259      * not.  The reason is that invalid requests are accounted during their
 260      * submission, therefore there's no actual I/O involved.
 261      */
 262     qemu_mutex_lock(&stats->lock);
 263     stats->invalid_ops[type]++;
 264
 265     if (stats->account_invalid) {
 266         stats->last_access_time_ns = qemu_clock_get_ns(clock_type);
 267     }
 268     qemu_mutex_unlock(&stats->lock);
 269 }
 270
 271 void block_acct_merge_done(BlockAcctStats *stats, enum BlockAcctType type,
 272                       int num_requests)
 273 {
 274     assert(type < BLOCK_MAX_IOTYPE);
 275
 276     qemu_mutex_lock(&stats->lock);
 277     stats->merged[type] += num_requests;
 278     qemu_mutex_unlock(&stats->lock);
 279 }
 280
 281 int64_t block_acct_idle_time_ns(BlockAcctStats *stats)
 282 {
 283     return qemu_clock_get_ns(clock_type) - stats->last_access_time_ns;
 284 }
 285
 286 double block_acct_queue_depth(BlockAcctTimedStats *stats,
 287                               enum BlockAcctType type)
 288 {
 289     uint64_t sum, elapsed;
 290
 291     assert(type < BLOCK_MAX_IOTYPE);
 292
 293     qemu_mutex_lock(&stats->stats->lock);
 294     sum = timed_average_sum(&stats->latency[type], &elapsed);
 295     qemu_mutex_unlock(&stats->stats->lock);
 296
 297     return (double) sum / elapsed;
 298 }