text: /*
   * QEMU System Emulator block accounting
   *
   * Copyright (c) 2011 Christoph Hellwig
   * Copyright (c) 2015 Igalia, S.L.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  #ifndef BLOCK_ACCOUNTING_H
  #define BLOCK_ACCOUNTING_H
  
  #include "qemu/timed-average.h"
  #include "qemu/thread.h"
  #include "qapi/qapi-builtin-types.h"
  
  typedef struct BlockAcctTimedStats BlockAcctTimedStats;
  typedef struct BlockAcctStats BlockAcctStats;
  
  enum BlockAcctType {
      BLOCK_ACCT_READ,
      BLOCK_ACCT_WRITE,
      BLOCK_ACCT_FLUSH,
      BLOCK_MAX_IOTYPE,
  };
  
  struct BlockAcctTimedStats {
      BlockAcctStats *stats;
      TimedAverage latency[BLOCK_MAX_IOTYPE];
      unsigned interval_length; /* in seconds */
      QSLIST_ENTRY(BlockAcctTimedStats) entries;
  };
  
  typedef struct BlockLatencyHistogram {
      /* The following histogram is represented like this:
       *
       * 5|           *
       * 4|           *
       * 3| *         *
       * 2| *         *    *
       * 1| *    *    *    *
       *  +------------------
       *      10   50   100
       *
       * BlockLatencyHistogram histogram = {
       *     .nbins = 4,
       *     .boundaries = {10, 50, 100},
       *     .bins = {3, 1, 5, 2},
       * };
       *
       * @boundaries array define histogram intervals as follows:
       * [0, boundaries[0]), [boundaries[0], boundaries[1]), ...
       * [boundaries[nbins-2], +inf)
       *
       * So, for example above, histogram intervals are:
       * [0, 10), [10, 50), [50, 100), [100, +inf)
       */
      int nbins;
      uint64_t *boundaries; /* @nbins-1 numbers here
                               (all boundaries, except 0 and +inf) */
      uint64_t *bins;
  } BlockLatencyHistogram;
  
  struct BlockAcctStats {
      QemuMutex lock;
      uint64_t nr_bytes[BLOCK_MAX_IOTYPE];
      uint64_t nr_ops[BLOCK_MAX_IOTYPE];
      uint64_t invalid_ops[BLOCK_MAX_IOTYPE];
      uint64_t failed_ops[BLOCK_MAX_IOTYPE];
      uint64_t total_time_ns[BLOCK_MAX_IOTYPE];
      uint64_t merged[BLOCK_MAX_IOTYPE];
      int64_t last_access_time_ns;
      QSLIST_HEAD(, BlockAcctTimedStats) intervals;
      bool account_invalid;
      bool account_failed;
      BlockLatencyHistogram latency_histogram[BLOCK_MAX_IOTYPE];
  };
  
  typedef struct BlockAcctCookie {
      int64_t bytes;
      int64_t start_time_ns;
      enum BlockAcctType type;
  } BlockAcctCookie;
  
  void block_acct_init(BlockAcctStats *stats);
  void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
                       bool account_failed);
  void block_acct_cleanup(BlockAcctStats *stats);
  void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length);
  BlockAcctTimedStats *block_acct_interval_next(BlockAcctStats *stats,
                                                BlockAcctTimedStats *s);
  void block_acct_start(BlockAcctStats *stats, BlockAcctCookie *cookie,
                        int64_t bytes, enum BlockAcctType type);
  void block_acct_done(BlockAcctStats *stats, BlockAcctCookie *cookie);
  void block_acct_failed(BlockAcctStats *stats, BlockAcctCookie *cookie);
  void block_acct_invalid(BlockAcctStats *stats, enum BlockAcctType type);
  void block_acct_merge_done(BlockAcctStats *stats, enum BlockAcctType type,
                             int num_requests);
  int64_t block_acct_idle_time_ns(BlockAcctStats *stats);
  double block_acct_queue_depth(BlockAcctTimedStats *stats,
                                enum BlockAcctType type);
  int block_latency_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
                                  uint64List *boundaries);
  void block_latency_histograms_clear(BlockAcctStats *stats);
  
  #endif
  