doc/man/lttng-track.1.txt

   1 lttng-track(1)
   2 ==============
   3
   4
   5 NAME
   6 ----
   7 lttng-track - Add one or more entries to an LTTng resource tracker
   8
   9
  10 SYNOPSIS
  11 --------
  12 [verse]
  13 *lttng* ['GENERAL OPTIONS'] *track* (option:--kernel | option:--userspace)
  14       [option:--session='SESSION'] (option:--pid='PID'[,'PID']... | option:--all option:--pid)
  15
  16
  17 DESCRIPTION
  18 -----------
  19 The `lttng track` commands adds one or more entries to a
  20 resource tracker.
  21
  22 A resource tracker is a _whitelist_ of resources. Tracked resources are
  23 allowed to emit events, provided those events are targeted by enabled
  24 event rules (see linklttng:lttng-enable-event(1)).
  25
  26 Tracker entries can be removed from the whitelist with
  27 linklttng:lttng-untrack(1).
  28
  29 As of this version, the only available tracker is the *PID tracker*. The
  30 process ID (PID) tracker follows one or more process IDs; only the
  31 processes with a tracked PID are allowed to emit events. By default, all
  32 possible PIDs on the system are tracked: any process may emit enabled
  33 events (equivalent of `lttng track --pid --all` for all domains).
  34
  35 With the PID tracker, it is possible, for example, to record all system
  36 calls called by a given process:
  37
  38 -------------------------------------------
  39 lttng enable-event --kernel --all --syscall
  40 lttng track --kernel --pid=2345
  41 lttng start
  42 -------------------------------------------
  43
  44 If all the PIDs are tracked (i.e. `lttng track --pid --all`, which is
  45 the default state of all domains when creating a tracing session), then
  46 using the track command with one or more specific PIDs has the effect of
  47 first removing all the PIDs from the whitelist, then adding the
  48 specified PIDs.
  49
  50
  51 Example
  52 ~~~~~~~
  53 Assume the maximum system PID is 7 for this example.
  54
  55 Initial whitelist:
  56
  57 -------------------------------
  58 [0] [1] [2] [3] [4] [5] [6] [7]
  59 -------------------------------
  60
  61 Command:
  62
  63 -----------------------------------
  64 lttng track --userspace --pid=3,6,7
  65 -----------------------------------
  66
  67 Whitelist:
  68
  69 -------------------------------
  70 [ ] [ ] [ ] [3] [ ] [ ] [6] [7]
  71 -------------------------------
  72
  73 Command:
  74
  75 ---------------------------------
  76 lttng untrack --userspace --pid=7
  77 ---------------------------------
  78
  79 Whitelist:
  80
  81 -------------------------------
  82 [ ] [ ] [ ] [3] [ ] [ ] [6] [ ]
  83 -------------------------------
  84
  85 Command:
  86
  87 ---------------------------------
  88 lttng track --userspace --pid=1,5
  89 ---------------------------------
  90
  91 Whitelist:
  92
  93 -------------------------------
  94 [ ] [1] [ ] [3] [ ] [5] [6] [ ]
  95 -------------------------------
  96
  97 It should be noted that the PID tracker tracks the numeric process IDs.
  98 Should a process with a given ID exit and another process be given this
  99 ID, then the latter would also be allowed to emit events.
 100
 101 See the linklttng:lttng-untrack(1) for more details about removing
 102 entries.
 103
 104
 105 include::common-cmd-options-head.txt[]
 106
 107
 108 Domain
 109 ~~~~~~
 110 One of:
 111
 112 option:-k, option:--kernel::
 113     Track resources in the Linux kernel domain.
 114
 115 option:-u, option:--userspace::
 116     Track resources in the user space domain.
 117
 118
 119 Target
 120 ~~~~~~
 121 option:-s, option:--session='SESSION'::
 122     Track resources in the tracing session named 'SESSION' instead of
 123     the current tracing session.
 124
 125
 126 Tracking
 127 ~~~~~~~~
 128 option:-a, option:--all::
 129     Used in conjunction with an empty option:--pid option: track _all_
 130     process IDs (add all entries to the whitelist).
 131
 132 option:-p, option:--pid[='PID'[,'PID']...]::
 133     Track process IDs 'PID' (add them to the current whitelist).
 134 +
 135 The 'PID' argument must be omitted when also using the option:--all
 136 option.
 137
 138
 139 include::common-cmd-help-options.txt[]
 140
 141
 142 include::common-cmd-footer.txt[]
 143
 144
 145 SEE ALSO
 146 --------
 147 linklttng:lttng-untrack(1),
 148 linklttng:lttng(1)