qemu/block/accounting.c
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   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
  32static QEMUClockType clock_type = QEMU_CLOCK_REALTIME;
  33static const int qtest_latency_ns = NANOSECONDS_PER_SECOND / 1000;
  34
  35void 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
  45static 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
  59void 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
  68void 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
  77void 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
  95BlockAcctTimedStats *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
 105void 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 */
 121static 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
 130static 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
 159int 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
 191void 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
 203static 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
 244void block_acct_done(BlockAcctStats *stats, BlockAcctCookie *cookie)
 245{
 246    block_account_one_io(stats, cookie, false);
 247}
 248
 249void block_acct_failed(BlockAcctStats *stats, BlockAcctCookie *cookie)
 250{
 251    block_account_one_io(stats, cookie, true);
 252}
 253
 254void 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
 271void 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
 281int64_t block_acct_idle_time_ns(BlockAcctStats *stats)
 282{
 283    return qemu_clock_get_ns(clock_type) - stats->last_access_time_ns;
 284}
 285
 286double 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}
 299