| 1 | lttng-add-context(1) |
| 2 | ==================== |
| 3 | :revdate: 6 May 2021 |
| 4 | |
| 5 | |
| 6 | NAME |
| 7 | ---- |
| 8 | lttng-add-context - Add context fields to be recorded by LTTng |
| 9 | |
| 10 | |
| 11 | SYNOPSIS |
| 12 | -------- |
| 13 | Add context fields to be recorded to the event records of one or more |
| 14 | channels: |
| 15 | |
| 16 | [verse] |
| 17 | *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *add-context* |
| 18 | (option:--kernel | option:--userspace | option:--jul | option:--log4j) |
| 19 | [option:--session='SESSION'] [option:--channel='CHANNEL'] |
| 20 | option:--type='TYPE' [option:--type='TYPE']... |
| 21 | |
| 22 | List the available context field types: |
| 23 | |
| 24 | [verse] |
| 25 | *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *add-context* option:--list |
| 26 | |
| 27 | |
| 28 | DESCRIPTION |
| 29 | ----------- |
| 30 | The `lttng add-context` command can: |
| 31 | |
| 32 | Without the option:--list option:: |
| 33 | Add one or more context fields to be recorded by LTTng to the event |
| 34 | records of: |
| 35 | + |
| 36 | With the option:--session='SESSION' option::: |
| 37 | The tracing session named 'SESSION'. |
| 38 | |
| 39 | Without the option:--session option::: |
| 40 | The current tracing session (see man:lttng-concepts(7) to learn more |
| 41 | about the current tracing session). |
| 42 | |
| 43 | With the option:--channel='CHANNEL'::: |
| 44 | The channel named 'CHANNEL'. |
| 45 | |
| 46 | Without the option:--channel option::: |
| 47 | *All* the channels of the selected tracing session. |
| 48 | |
| 49 | With the option:--list option:: |
| 50 | List the available context field types. |
| 51 | |
| 52 | See man:lttng-concepts(7) to learn more about tracing sessions and |
| 53 | channels. |
| 54 | |
| 55 | Repeat the option:--type='TYPE' option to add more than one context |
| 56 | field to be recorded. 'TYPE' is one of: |
| 57 | |
| 58 | * A statically-known, or built-in context field named. |
| 59 | |
| 60 | * A perf counter name: |
| 61 | + |
| 62 | -- |
| 63 | Per-CPU:: |
| 64 | Prefix: `perf:cpu:` |
| 65 | + |
| 66 | Only available with the option:--kernel option. |
| 67 | |
| 68 | Per-thread:: |
| 69 | Prefix: `perf:thread:` |
| 70 | + |
| 71 | Only available with the option:--userspace, option:--jul, or |
| 72 | option:--log4j option. |
| 73 | -- |
| 74 | + |
| 75 | Add Performance Monitoring Unit (PMU) counter context fields by raw ID |
| 76 | with the ++perf:cpu:raw:r++__N__++:++__NAME__ (option:--kernel option) |
| 77 | or ++perf:thread:raw:r++__N__++:++__NAME__ (option:--userspace, |
| 78 | option:--jul, or option:--log4j option) types, with: |
| 79 | + |
| 80 | -- |
| 81 | 'N':: |
| 82 | A hexadecimal event descriptor which follows the man:perf-record(1) |
| 83 | format: a concatenation of the event number and umask value which |
| 84 | the manufacturer of the processor provides. |
| 85 | + |
| 86 | The possible values for this part are processor-specific. |
| 87 | |
| 88 | 'NAME':: |
| 89 | Custom name to identify the counter. |
| 90 | -- |
| 91 | |
| 92 | * An LTTng application-specific context field name: |
| 93 | + |
| 94 | -- |
| 95 | [verse] |
| 96 | $app.'PROVIDER':__TYPE__ |
| 97 | + |
| 98 | 'PROVIDER':: |
| 99 | Provider name. |
| 100 | |
| 101 | 'TYPE':: |
| 102 | Context type name. |
| 103 | -- |
| 104 | + |
| 105 | Only available with the option:--jul and option:--log4j options. |
| 106 | |
| 107 | IMPORTANT: Make sure to **single-quote** 'TYPE' when you run the |
| 108 | `add-context` command from a shell, as `$` is a special character for |
| 109 | variable substitution in most shells. |
| 110 | |
| 111 | NOTE: As of LTTng{nbsp}{lttng_version}, you may :not: add context fields |
| 112 | to be recorded to the event records of a given channel once its tracing |
| 113 | session has been started (see man:lttng-start(1)) at least once. |
| 114 | |
| 115 | See the <<examples,EXAMPLES>> section below for usage examples. |
| 116 | |
| 117 | |
| 118 | include::common-lttng-cmd-options-head.txt[] |
| 119 | |
| 120 | |
| 121 | Tracing domain |
| 122 | ~~~~~~~~~~~~~~ |
| 123 | One of: |
| 124 | |
| 125 | option:-j, option:--jul:: |
| 126 | Add context fields to be recorded to the event records of one or |
| 127 | more channels of the `java.util.logging` (JUL) tracing domain. |
| 128 | |
| 129 | option:-k, option:--kernel:: |
| 130 | Add context fields to be recorded to the event records of one or |
| 131 | more channels of the Linux kernel tracing domain. |
| 132 | |
| 133 | option:-l, option:--log4j:: |
| 134 | Add context fields to be recorded to the event records of one or |
| 135 | more channels of the Apache log4j tracing domain. |
| 136 | |
| 137 | option:-u, option:--userspace:: |
| 138 | Add context fields to be recorded to the event records of one or |
| 139 | more channels of the user space tracing domain. |
| 140 | |
| 141 | |
| 142 | Recording target |
| 143 | ~~~~~~~~~~~~~~~~ |
| 144 | option:-c 'CHANNEL', option:--channel='CHANNEL':: |
| 145 | Add context fields to be recorded to the event records of a channel |
| 146 | named 'CHANNEL' instead of all the channels of the selected |
| 147 | tracing session. |
| 148 | |
| 149 | option:-s 'SESSION', option:--session='SESSION':: |
| 150 | Add context fields to be recorded to the event records of one or |
| 151 | more channels of the tracing session named 'SESSION' instead of the |
| 152 | current tracing session. |
| 153 | |
| 154 | |
| 155 | Context field type |
| 156 | ~~~~~~~~~~~~~~~~~~ |
| 157 | option:--list:: |
| 158 | List the available context field types. |
| 159 | + |
| 160 | You may :not: use this option with the option:--channel, |
| 161 | option:--session, or option:--type options. |
| 162 | |
| 163 | option:-t 'TYPE', option:--type='TYPE':: |
| 164 | Add a context field having the type 'TYPE' to be recorded. |
| 165 | + |
| 166 | Repeat this option to add more than one context field. |
| 167 | |
| 168 | |
| 169 | include::common-lttng-cmd-help-options.txt[] |
| 170 | |
| 171 | |
| 172 | include::common-lttng-cmd-after-options.txt[] |
| 173 | |
| 174 | |
| 175 | [[examples]] |
| 176 | EXAMPLES |
| 177 | -------- |
| 178 | .List the available context field types. |
| 179 | ==== |
| 180 | See the option:--list option. |
| 181 | |
| 182 | [role="term"] |
| 183 | ---- |
| 184 | $ lttng add-context --list |
| 185 | ---- |
| 186 | ==== |
| 187 | |
| 188 | .Add a single statically-known context field to be recorded to all the Linux kernel channels of the current tracing session. |
| 189 | ==== |
| 190 | [role="term"] |
| 191 | ---- |
| 192 | $ lttng add-context --kernel --type=pid |
| 193 | ---- |
| 194 | ==== |
| 195 | |
| 196 | .Add three statically-known context fields to be recorded to a specific user space channel of a specific tracing session. |
| 197 | ==== |
| 198 | [role="term"] |
| 199 | ---- |
| 200 | $ lttng add-context --userspace --session=my-session \ |
| 201 | --channel=my-channel \ |
| 202 | --type=vpid --type=procname --type=ip |
| 203 | ---- |
| 204 | ==== |
| 205 | |
| 206 | .Add a perf counter context field to be recorded to a specific Linux kernel channel of the current tracing session. |
| 207 | ==== |
| 208 | [role="term"] |
| 209 | ---- |
| 210 | $ lttng add-context --kernel --channel=my-channel \ |
| 211 | --type=perf:cpu:cache-misses |
| 212 | ---- |
| 213 | ==== |
| 214 | |
| 215 | .Add an LTTng application-specific context field to be recorded to all the JUL channels of the current tracing session. |
| 216 | ==== |
| 217 | [role="term"] |
| 218 | ---- |
| 219 | $ lttng add-context --jul --type='$app.my_server:user_cnt' |
| 220 | ---- |
| 221 | ==== |
| 222 | |
| 223 | |
| 224 | include::common-footer.txt[] |
| 225 | |
| 226 | |
| 227 | SEE ALSO |
| 228 | -------- |
| 229 | man:lttng(1), |
| 230 | man:lttng-enable-channel(1), |
| 231 | man:lttng-concepts(7) |