doc/man/lttng-add-context.1.txt

   1 lttng-add-context(1)
   2 ====================
   3
   4
   5 NAME
   6 ----
   7 lttng-add-context - Add context fields to an LTTng channel
   8
   9
  10 SYNOPSIS
  11 --------
  12 Add context fields to a channel:
  13
  14 [verse]
  15 *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *add-context*
  16       (option:--kernel | option:--userspace | option:--jul | option:--log4j)
  17       [option:--session='SESSION'] [option:--channel='CHANNEL']
  18       option:--type='TYPE' [option:--type='TYPE']...
  19
  20 List the available context fields:
  21
  22 [verse]
  23 *lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *add-context* option:--list
  24
  25
  26 DESCRIPTION
  27 -----------
  28 The `lttng add-context` command adds one or more context fields to a
  29 channel.
  30
  31 Channels are created with the man:lttng-enable-channel(1) command.
  32
  33 When context fields are added to a channel, all the events emitted
  34 within this channel contain the dynamic values of those context fields.
  35
  36 If the option:--session option is omitted, the current tracing session
  37 is used. If the option:--channel option is omitted, the context fields
  38 are added to all the selected tracing session's channels.
  39
  40 Many context fields can be added to a channel at once by repeating the
  41 option:--type option.
  42
  43 perf counters are available as per-CPU (`perf:cpu:` prefix) as well as
  44 per-thread (`perf:thread:` prefix) counters. Currently, per-CPU counters
  45 can only be used in the Linux kernel tracing domain, while per-thread
  46 counters can only be used in the user space tracing domain.
  47
  48 It is also possible to enable PMU counters by raw ID using the
  49 `perf:cpu:raw:rN:NAME` (Linux kernel tracing domain) or
  50 `perf:thread:raw:rN:NAME` (user space tracing domain), with:
  51
  52 `N`::
  53     A hexadecimal event descriptor which is the same format as used
  54     by man:perf-record(1): a concatenation of the event number and umask
  55     value provided by the processor's manufacturer. The possible values
  56     for this field are processor-specific.
  57
  58 `NAME`::
  59     Custom name to easily recognize the counter.
  60
  61 Application-specific context fields can be added to a channel using the
  62 following syntax:
  63
  64 [verse]
  65 $app.'PROVIDER':__TYPE__
  66
  67 with:
  68
  69 'PROVIDER'::
  70     Provider name.
  71
  72 'TYPE'::
  73     Context type name.
  74
  75 NOTE: Make sure to **single-quote** the type when running the command
  76 from a shell, as `$` is a special character for variable substitution in
  77 most shells.
  78
  79 Use the option:--list option without other arguments to list the
  80 available context field names.
  81
  82
  83 include::common-cmd-options-head.txt[]
  84
  85
  86 Domain
  87 ~~~~~~
  88 One of:
  89
  90 option:-j, option:--jul::
  91     Add context to channel in the `java.util.logging` (JUL) domain.
  92
  93 option:-k, option:--kernel::
  94     Add context to channel in the Linux kernel domain.
  95
  96 option:-l, option:--log4j::
  97     Add context to channel in the Apache log4j domain.
  98
  99 option:-u, option:--userspace::
 100     Add context to channel in the user space domain.
 101
 102
 103 Target
 104 ~~~~~~
 105 option:-c 'CHANNEL', option:--channel='CHANNEL'::
 106     Add context fields to a channel named 'CHANNEL' instead of adding
 107     them to all the channels.
 108
 109 option:-s 'SESSION', option:--session='SESSION'::
 110     Add context fields to a channel in the tracing session named 'SESSION'
 111     instead of the current tracing session.
 112
 113
 114 Context
 115 ~~~~~~~
 116 option:--list::
 117     List the available context fields. Use this option alone.
 118
 119 option:-t 'TYPE', option:--type='TYPE'::
 120     Add context field named 'TYPE'. This option can be repeated as
 121     many times as needed on the command-line.
 122
 123
 124 include::common-cmd-help-options.txt[]
 125
 126
 127 include::common-cmd-footer.txt[]
 128
 129
 130 SEE ALSO
 131 --------
 132 man:lttng(1)