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authorMohamad Gebai <mohamad.gebai@gmail.com>2014-01-29 22:47:57 -0500
committerStefan Hajnoczi <stefanha@redhat.com>2014-02-19 11:08:54 +0100
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Update documentation for LTTng ust tracing
Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'docs')
-rw-r--r--docs/tracing.txt36
1 files changed, 36 insertions, 0 deletions
diff --git a/docs/tracing.txt b/docs/tracing.txt
index bfc261b..bf2e15c 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