| 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) |