Patchwork [v4,4/5] Update documentation for LTTng ust tracing

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Submitter Mohamad Gebai
Date Oct. 18, 2013, 6:39 a.m.
Message ID <1382078393-11195-5-git-send-email-mohamad.gebai@polymtl.ca>
Download mbox | patch
Permalink /patch/284449/
State New
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Comments

Mohamad Gebai - Oct. 18, 2013, 6:39 a.m.
Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
---
 docs/tracing.txt |   36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
Stefan Hajnoczi - Oct. 18, 2013, 2:02 p.m.
On Fri, Oct 18, 2013 at 02:39:52AM -0400, Mohamad Gebai wrote:
> +Package lttng-tools is required for userspace tracing. You must ensure that the
> +current user belongs to the "tracing" group, or manually launch the
> +lttng-sessiond daemon for the current user prior to running any instance of
> +Qemu.
> +
> +While running an instrumented Qemu, LTTng should be able to list all available
> +events:

s/Qemu/QEMU/g

Patch

diff --git a/docs/tracing.txt b/docs/tracing.txt
index bfc261b..d7be2fd 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -214,6 +214,42 @@  The "ust" backend uses the LTTng Userspace Tracer library.  There are no
 monitor commands built into QEMU, instead UST utilities should be used to list,
 enable/disable, and dump traces.
 
+Package lttng-tools is required for userspace tracing. You must ensure that the
+current user belongs to the "tracing" group, or manually launch the
+lttng-sessiond daemon for the current user prior to running any instance of
+Qemu.
+
+While running an instrumented Qemu, LTTng should be able to list all available
+events:
+
+    lttng list -u
+
+Create tracing session:
+
+    lttng create mysession
+
+Enable events:
+
+    lttng enable-event qemu:g_malloc -u
+
+Where the events can either be a comma-separated list of events, or "-a" to
+enable all tracepoint events. Start and stop tracing as needed:
+
+    lttng start
+    lttng stop
+
+View the trace:
+
+    lttng view
+
+Destroy tracing session:
+
+    lttng destroy
+
+Babeltrace can be used at any later time to view the trace:
+
+    babeltrace $HOME/lttng-traces/mysession-<date>-<time>
+
 === SystemTap ===
 
 The "dtrace" backend uses DTrace sdt probes but has only been tested with