projects / lttng-tools.git / blame
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|---|---|---|
| e7651054 DG |
1 | QUICKSTART |
| 2 | -------------- | |
| 3 | ||
| 4 | This is a quick start guide for the complete LTTng tool chain. This is divided | |
| 5 | in three sections respectively Kernel tracing, user-space tracing and reading a | |
| 6 | trace. | |
| 7 | ||
| 8 | See the README file for installation procedure or use the various Linux | |
| 9 | distribution packages. | |
| 10 | ||
| 11 | In order to trace the Kernel, you'll need the lttng-modules >= 2.0 compiled and | |
| 12 | installed. See http://lttng.org/content/lttng-kernel-tracer for more | |
| 13 | instructions for that part. For user-space tracing, you'll need an instrumented | |
| 14 | application, please see http://lttng.org/ust | |
| 15 | ||
| 16 | lttng-tools provide a session daemon (ltt-sessiond) that acts as a tracing | |
| 17 | registry. To trace any instrumented applications or the kernel, a registered | |
| 18 | tracing session is needed. | |
| 19 | ||
| 20 | To interact with the session daemon and a tracing session, you can use the | |
| 21 | lttng command line UI (lttng). | |
| 22 | ||
| 23 | The next sections explain how to do tracing :) | |
| 24 | ||
| 25 | Kernel Tracing | |
| 26 | -------------- | |
| 27 | ||
| 28 | You have to modprobe the lttng-modules manually or the session daemon will do | |
| 29 | it for you if they can be found on your system. | |
| 30 | ||
| 31 | You can then start the session daemon by hand or the lttng command line tool | |
| 32 | will do it for you. | |
| 33 | ||
| 34 | List possible kernel events: | |
| 35 | ||
| 36 | # lttng list -k | |
| 37 | ||
| 38 | 1) Create a tracing session. A .lttngrc will be created in $HOME containing | |
| 39 | the session name (here 'mysession') you are working on. | |
| 40 | ||
| 41 | # lttng create mysession | |
| 42 | ||
| 43 | 2) Enable event(s). Here for example, we want only 'sched_switch' and | |
| 44 | 'sys_enter' events for the kernel (-k/--kernel). | |
| 45 | ||
| 46 | # lttng enable-event sched_switch,sys_enter -k | |
| 47 | ||
| 48 | or enable ALL events (-a/--all): | |
| 49 | ||
| 50 | # lttng enable-event -a -k | |
| 51 | ||
| 52 | 3) Start tracing: | |
| 53 | ||
| 54 | # lttng start | |
| 55 | ||
| 56 | Tracing is in progress at this point and will be written in | |
| 57 | $HOME/lttng-traces/mysession-<date>-<time> | |
| 58 | ||
| 59 | 4) Stop tracing: | |
| 60 | ||
| 61 | # lttng stop | |
| 62 | ||
| 63 | 5) Destroy your session after you are done with tracing | |
| 64 | ||
| 65 | # lttng destroy | |
| 66 | ||
| 67 | User-space Tracing | |
| 68 | -------------- | |
| 69 | ||
| 70 | User-space tracer 2.0 not released at this point. You'll have to use 'ustctl' | |
| 71 | to control user-space tracing. | |
| 72 | ||
| 73 | Reading a trace | |
| 74 | -------------- | |
| 75 | ||
| 76 | To read your trace, you'll need babeltrace which will text dump your the trace. | |
| 77 | Please see http://www.efficios.com/ctf and git tree | |
| 78 | http://git.efficios.com/?p=babeltrace.git | |
| 79 | ||
| 80 | # babeltrace -n $HOME/lttng-traces/mysession-<date>-<time> | less | |
| 81 | ||
| 82 | Voilà! |