| | 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* ['linkgenoptions:(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 | [role="term"] |
| | 39 | ------------------------------------------- |
| | 40 | lttng enable-event --kernel --all --syscall |
| | 41 | lttng track --kernel --pid=2345 |
| | 42 | lttng start |
| | 43 | ------------------------------------------- |
| | 44 | |
| | 45 | If all the PIDs are tracked (i.e. `lttng track --pid --all`, which is |
| | 46 | the default state of all domains when creating a tracing session), then |
| | 47 | using the track command with one or more specific PIDs has the effect of |
| | 48 | first removing all the PIDs from the whitelist, then adding the |
| | 49 | specified PIDs. |
| | 50 | |
| | 51 | |
| | 52 | Example |
| | 53 | ~~~~~~~ |
| | 54 | Assume the maximum system PID is 7 for this example. |
| | 55 | |
| | 56 | Initial whitelist: |
| | 57 | |
| | 58 | ------------------------------- |
| | 59 | [0] [1] [2] [3] [4] [5] [6] [7] |
| | 60 | ------------------------------- |
| | 61 | |
| | 62 | Command: |
| | 63 | |
| | 64 | [role="term"] |
| | 65 | ----------------------------------- |
| | 66 | lttng track --userspace --pid=3,6,7 |
| | 67 | ----------------------------------- |
| | 68 | |
| | 69 | Whitelist: |
| | 70 | |
| | 71 | ------------------------------- |
| | 72 | [ ] [ ] [ ] [3] [ ] [ ] [6] [7] |
| | 73 | ------------------------------- |
| | 74 | |
| | 75 | Command: |
| | 76 | |
| | 77 | [role="term"] |
| | 78 | --------------------------------- |
| | 79 | lttng untrack --userspace --pid=7 |
| | 80 | --------------------------------- |
| | 81 | |
| | 82 | Whitelist: |
| | 83 | |
| | 84 | ------------------------------- |
| | 85 | [ ] [ ] [ ] [3] [ ] [ ] [6] [ ] |
| | 86 | ------------------------------- |
| | 87 | |
| | 88 | Command: |
| | 89 | |
| | 90 | [role="term"] |
| | 91 | --------------------------------- |
| | 92 | lttng track --userspace --pid=1,5 |
| | 93 | --------------------------------- |
| | 94 | |
| | 95 | Whitelist: |
| | 96 | |
| | 97 | ------------------------------- |
| | 98 | [ ] [1] [ ] [3] [ ] [5] [6] [ ] |
| | 99 | ------------------------------- |
| | 100 | |
| | 101 | It should be noted that the PID tracker tracks the numeric process IDs. |
| | 102 | Should a process with a given ID exit and another process be given this |
| | 103 | ID, then the latter would also be allowed to emit events. |
| | 104 | |
| | 105 | See the linklttng:lttng-untrack(1) for more details about removing |
| | 106 | entries. |
| | 107 | |
| | 108 | |
| | 109 | include::common-cmd-options-head.txt[] |
| | 110 | |
| | 111 | |
| | 112 | Domain |
| | 113 | ~~~~~~ |
| | 114 | One of: |
| | 115 | |
| | 116 | option:-k, option:--kernel:: |
| | 117 | Track resources in the Linux kernel domain. |
| | 118 | |
| | 119 | option:-u, option:--userspace:: |
| | 120 | Track resources in the user space domain. |
| | 121 | |
| | 122 | |
| | 123 | Target |
| | 124 | ~~~~~~ |
| | 125 | option:-s, option:--session='SESSION':: |
| | 126 | Track resources in the tracing session named 'SESSION' instead of |
| | 127 | the current tracing session. |
| | 128 | |
| | 129 | |
| | 130 | Tracking |
| | 131 | ~~~~~~~~ |
| | 132 | option:-a, option:--all:: |
| | 133 | Used in conjunction with an empty option:--pid option: track _all_ |
| | 134 | process IDs (add all entries to the whitelist). |
| | 135 | |
| | 136 | option:-p, option:--pid[='PID'[,'PID']...]:: |
| | 137 | Track process IDs 'PID' (add them to the current whitelist). |
| | 138 | + |
| | 139 | The 'PID' argument must be omitted when also using the option:--all |
| | 140 | option. |
| | 141 | |
| | 142 | |
| | 143 | include::common-cmd-help-options.txt[] |
| | 144 | |
| | 145 | |
| | 146 | include::common-cmd-footer.txt[] |
| | 147 | |
| | 148 | |
| | 149 | SEE ALSO |
| | 150 | -------- |
| | 151 | linklttng:lttng-untrack(1), |
| | 152 | linklttng:lttng(1) |
projects / lttng-tools.git / blame_incremental