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[PULL,4/6] Update documentation for LTTng ust tracing

Message ID 1392824759-7093-5-git-send-email-stefanha@redhat.com
State New
Headers show

Commit Message

Stefan Hajnoczi Feb. 19, 2014, 3:45 p.m. UTC 
From: Mohamad Gebai <mohamad.gebai@gmail.com>

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>
---
 docs/tracing.txt | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
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Patch

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