migration/migration-stats.h

   1 /*
   2  * Migration stats
   3  *
   4  * Copyright (c) 2012-2023 Red Hat Inc
   5  *
   6  * Authors:
   7  *  Juan Quintela <quintela@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #ifndef QEMU_MIGRATION_STATS_H
  14 #define QEMU_MIGRATION_STATS_H
  15
  16 #include "qemu/stats64.h"
  17
  18 /*
  19  * Amount of time to allocate to each "chunk" of bandwidth-throttled
  20  * data.
  21  */
  22 #define BUFFER_DELAY     100
  23
  24 /*
  25  * If rate_limit_max is 0, there is special code to remove the rate
  26  * limit.
  27  */
  28 #define RATE_LIMIT_DISABLED 0
  29
  30 /*
  31  * These are the ram migration statistic counters.  It is loosely
  32  * based on MigrationStats.  We change to Stat64 any counter that
  33  * needs to be updated using atomic ops (can be accessed by more than
  34  * one thread).
  35  */
  36 typedef struct {
  37     /*
  38      * Number of bytes that were dirty last time that we synced with
  39      * the guest memory.  We use that to calculate the downtime.  As
  40      * the remaining dirty amounts to what we know that is still dirty
  41      * since last iteration, not counting what the guest has dirtied
  42      * since we synchronized bitmaps.
  43      */
  44     Stat64 dirty_bytes_last_sync;
  45     /*
  46      * Number of pages dirtied per second.
  47      */
  48     Stat64 dirty_pages_rate;
  49     /*
  50      * Number of times we have synchronized guest bitmaps.
  51      */
  52     Stat64 dirty_sync_count;
  53     /*
  54      * Number of times zero copy failed to send any page using zero
  55      * copy.
  56      */
  57     Stat64 dirty_sync_missed_zero_copy;
  58     /*
  59      * Number of bytes sent at migration completion stage while the
  60      * guest is stopped.
  61      */
  62     Stat64 downtime_bytes;
  63     /*
  64      * Number of bytes sent through multifd channels.
  65      */
  66     Stat64 multifd_bytes;
  67     /*
  68      * Number of pages transferred that were not full of zeros.
  69      */
  70     Stat64 normal_pages;
  71     /*
  72      * Number of bytes sent during postcopy.
  73      */
  74     Stat64 postcopy_bytes;
  75     /*
  76      * Number of postcopy page faults that we have handled during
  77      * postcopy stage.
  78      */
  79     Stat64 postcopy_requests;
  80     /*
  81      * Number of bytes sent during precopy stage.
  82      */
  83     Stat64 precopy_bytes;
  84     /*
  85      * Amount of transferred data at the start of current cycle.
  86      */
  87     Stat64 rate_limit_start;
  88     /*
  89      * Maximum amount of data we can send in a cycle.
  90      */
  91     Stat64 rate_limit_max;
  92     /*
  93      * Total number of bytes transferred.
  94      */
  95     Stat64 transferred;
  96     /*
  97      * Number of pages transferred that were full of zeros.
  98      */
  99     Stat64 zero_pages;
 100 } MigrationAtomicStats;
 101
 102 extern MigrationAtomicStats mig_stats;
 103
 104 /**
 105  * migration_rate_get: Get the maximum amount that can be transferred.
 106  *
 107  * Returns the maximum number of bytes that can be transferred in a cycle.
 108  */
 109 uint64_t migration_rate_get(void);
 110
 111 /**
 112  * migration_rate_reset: Reset the rate limit counter.
 113  *
 114  * This is called when we know we start a new transfer cycle.
 115  *
 116  * @f: QEMUFile used for main migration channel
 117  */
 118 void migration_rate_reset(QEMUFile *f);
 119
 120 /**
 121  * migration_rate_set: Set the maximum amount that can be transferred.
 122  *
 123  * Sets the maximum amount of bytes that can be transferred in one cycle.
 124  *
 125  * @new_rate: new maximum amount
 126  */
 127 void migration_rate_set(uint64_t new_rate);
 128
 129 /**
 130  * migration_transferred_bytes: Return number of bytes transferred
 131  *
 132  * @f: QEMUFile used for main migration channel
 133  *
 134  * Returns how many bytes have we transferred since the beginning of
 135  * the migration.  It accounts for bytes sent through any migration
 136  * channel, multifd, qemu_file, rdma, ....
 137  */
 138 uint64_t migration_transferred_bytes(QEMUFile *f);
 139 #endif