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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 | ||
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70 | User-space tracer 2.0 not released at this point. For the 0.x versions, |
71 | you need to use 'ustctl' to control user-space tracing. | |
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72 | |
73 | Reading a trace | |
74 | -------------- | |
75 | ||
1aa502dd MD |
76 | To read your trace, you can use babeltrace which will text dump your the |
77 | trace. Please see http://www.efficios.com/ctf and git tree | |
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78 | http://git.efficios.com/?p=babeltrace.git |
79 | ||
80 | # babeltrace -n $HOME/lttng-traces/mysession-<date>-<time> | less | |
81 | ||
82 | VoilĂ ! |