include/block/accounting.h

/*
 * 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_NONE = 0,
    BLOCK_ACCT_READ,
    BLOCK_ACCT_WRITE,
    BLOCK_ACCT_FLUSH,
    BLOCK_ACCT_UNMAP,
    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