qapi/stats.json

   1 # -*- Mode: Python -*-
   2 # vim: filetype=python
   3 #
   4 # Copyright (c) 2022 Oracle and/or its affiliates.
   5 #
   6 # This work is licensed under the terms of the GNU GPL, version 2 or later.
   7 # See the COPYING file in the top-level directory.
   8 #
   9 # SPDX-License-Identifier: GPL-2.0-or-later
  10
  11 ##
  12 # = Statistics
  13 ##
  14
  15 ##
  16 # @StatsType:
  17 #
  18 # Enumeration of statistics types
  19 #
  20 # @cumulative: stat is cumulative; value can only increase.
  21 # @instant: stat is instantaneous; value can increase or decrease.
  22 # @peak: stat is the peak value; value can only increase.
  23 # @linear-histogram: stat is a linear histogram.
  24 # @log2-histogram: stat is a logarithmic histogram, with one bucket
  25 #                  for each power of two.
  26 #
  27 # Since: 7.1
  28 ##
  29 { 'enum' : 'StatsType',
  30   'data' : [ 'cumulative', 'instant', 'peak', 'linear-histogram',
  31              'log2-histogram' ] }
  32
  33 ##
  34 # @StatsUnit:
  35 #
  36 # Enumeration of unit of measurement for statistics
  37 #
  38 # @bytes: stat reported in bytes.
  39 # @seconds: stat reported in seconds.
  40 # @cycles: stat reported in clock cycles.
  41 #
  42 # Since: 7.1
  43 ##
  44 { 'enum' : 'StatsUnit',
  45   'data' : [ 'bytes', 'seconds', 'cycles' ] }
  46
  47 ##
  48 # @StatsProvider:
  49 #
  50 # Enumeration of statistics providers.
  51 #
  52 # Since: 7.1
  53 ##
  54 { 'enum': 'StatsProvider',
  55   'data': [ 'kvm' ] }
  56
  57 ##
  58 # @StatsTarget:
  59 #
  60 # The kinds of objects on which one can request statistics.
  61 #
  62 # @vm: statistics that apply to the entire virtual machine or
  63 #      the entire QEMU process.
  64 #
  65 # @vcpu: statistics that apply to a single virtual CPU.
  66 #
  67 # Since: 7.1
  68 ##
  69 { 'enum': 'StatsTarget',
  70   'data': [ 'vm', 'vcpu' ] }
  71
  72 ##
  73 # @StatsRequest:
  74 #
  75 # Indicates a set of statistics that should be returned by query-stats.
  76 #
  77 # @provider: provider for which to return statistics.
  78
  79 # @names: statistics to be returned (all if omitted).
  80 #
  81 # Since: 7.1
  82 ##
  83 { 'struct': 'StatsRequest',
  84   'data': { 'provider': 'StatsProvider',
  85             '*names': [ 'str' ] } }
  86
  87 ##
  88 # @StatsVCPUFilter:
  89 #
  90 # @vcpus: list of QOM paths for the desired vCPU objects.
  91 #
  92 # Since: 7.1
  93 ##
  94 { 'struct': 'StatsVCPUFilter',
  95   'data': { '*vcpus': [ 'str' ] } }
  96
  97 ##
  98 # @StatsFilter:
  99 #
 100 # The arguments to the query-stats command; specifies a target for which to
 101 # request statistics and optionally the required subset of information for
 102 # that target:
 103 # - which vCPUs to request statistics for
 104 # - which providers to request statistics from
 105 # - which named values to return within each provider
 106 #
 107 # Since: 7.1
 108 ##
 109 { 'union': 'StatsFilter',
 110   'base': {
 111       'target': 'StatsTarget',
 112       '*providers': [ 'StatsRequest' ] },
 113   'discriminator': 'target',
 114   'data': { 'vcpu': 'StatsVCPUFilter' } }
 115
 116 ##
 117 # @StatsValue:
 118 #
 119 # @scalar: single unsigned 64-bit integers.
 120 # @list: list of unsigned 64-bit integers (used for histograms).
 121 #
 122 # Since: 7.1
 123 ##
 124 { 'alternate': 'StatsValue',
 125   'data': { 'scalar': 'uint64',
 126             'list': [ 'uint64' ] } }
 127
 128 ##
 129 # @Stats:
 130 #
 131 # @name: name of stat.
 132 # @value: stat value.
 133 #
 134 # Since: 7.1
 135 ##
 136 { 'struct': 'Stats',
 137   'data': { 'name': 'str',
 138             'value' : 'StatsValue' } }
 139
 140 ##
 141 # @StatsResult:
 142 #
 143 # @provider: provider for this set of statistics.
 144 #
 145 # @qom-path: Path to the object for which the statistics are returned,
 146 #            if the object is exposed in the QOM tree
 147 #
 148 # @stats: list of statistics.
 149 #
 150 # Since: 7.1
 151 ##
 152 { 'struct': 'StatsResult',
 153   'data': { 'provider': 'StatsProvider',
 154             '*qom-path': 'str',
 155             'stats': [ 'Stats' ] } }
 156
 157 ##
 158 # @query-stats:
 159 #
 160 # Return runtime-collected statistics for objects such as the
 161 # VM or its vCPUs.
 162 #
 163 # The arguments are a StatsFilter and specify the provider and objects
 164 # to return statistics about.
 165 #
 166 # Returns: a list of StatsResult, one for each provider and object
 167 #          (e.g., for each vCPU).
 168 #
 169 # Since: 7.1
 170 ##
 171 { 'command': 'query-stats',
 172   'data': 'StatsFilter',
 173   'boxed': true,
 174   'returns': [ 'StatsResult' ] }
 175
 176 ##
 177 # @StatsSchemaValue:
 178 #
 179 # Schema for a single statistic.
 180 #
 181 # @name: name of the statistic; each element of the schema is uniquely
 182 #        identified by a target, a provider (both available in @StatsSchema)
 183 #        and the name.
 184 #
 185 # @type: kind of statistic.
 186 #
 187 # @unit: basic unit of measure for the statistic; if missing, the statistic
 188 #        is a simple number or counter.
 189 #
 190 # @base: base for the multiple of @unit in which the statistic is measured.
 191 #        Only present if @exponent is non-zero; @base and @exponent together
 192 #        form a SI prefix (e.g., _nano-_ for ``base=10`` and ``exponent=-9``)
 193 #        or IEC binary prefix (e.g. _kibi-_ for ``base=2`` and ``exponent=10``)
 194 #
 195 # @exponent: exponent for the multiple of @unit in which the statistic is
 196 #            expressed, or 0 for the basic unit
 197 #
 198 # @bucket-size: Present when @type is "linear-histogram", contains the width
 199 #               of each bucket of the histogram.
 200 #
 201 # Since: 7.1
 202 ##
 203 { 'struct': 'StatsSchemaValue',
 204   'data': { 'name': 'str',
 205             'type': 'StatsType',
 206             '*unit': 'StatsUnit',
 207             '*base': 'int8',
 208             'exponent': 'int16',
 209             '*bucket-size': 'uint32' } }
 210
 211 ##
 212 # @StatsSchema:
 213 #
 214 # Schema for all available statistics for a provider and target.
 215 #
 216 # @provider: provider for this set of statistics.
 217 #
 218 # @target: the kind of object that can be queried through the provider.
 219 #
 220 # @stats: list of statistics.
 221 #
 222 # Since: 7.1
 223 ##
 224 { 'struct': 'StatsSchema',
 225   'data': { 'provider': 'StatsProvider',
 226             'target': 'StatsTarget',
 227             'stats': [ 'StatsSchemaValue' ] } }
 228
 229 ##
 230 # @query-stats-schemas:
 231 #
 232 # Return the schema for all available runtime-collected statistics.
 233 #
 234 # Note: runtime-collected statistics and their names fall outside QEMU's usual
 235 #       deprecation policies.  QEMU will try to keep the set of available data
 236 #       stable, together with their names, but will not guarantee stability
 237 #       at all costs; the same is true of providers that source statistics
 238 #       externally, e.g. from Linux.  For example, if the same value is being
 239 #       tracked with different names on different architectures or by different
 240 #       providers, one of them might be renamed.  A statistic might go away if
 241 #       an algorithm is changed or some code is removed; changing a default
 242 #       might cause previously useful statistics to always report 0.  Such
 243 #       changes, however, are expected to be rare.
 244 #
 245 # Since: 7.1
 246 ##
 247 { 'command': 'query-stats-schemas',
 248   'data': { '*provider': 'StatsProvider' },
 249   'returns': [ 'StatsSchema' ] }