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author | Mohamad Gebai <mohamad.gebai@gmail.com> | 2014-01-29 22:47:57 -0500 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2014-02-19 11:08:54 +0100 |
commit | ef3ef4a0408743f3d562cda413e00afb7b782d6b (patch) | |
tree | 2dcb14b0d2c59640d7fa74c61eb9951e5a696f67 /docs | |
parent | e6bf23f82d2d907dc99cf2581b4852417843a42d (diff) | |
download | qemu-ef3ef4a0408743f3d562cda413e00afb7b782d6b.zip qemu-ef3ef4a0408743f3d562cda413e00afb7b782d6b.tar.gz qemu-ef3ef4a0408743f3d562cda413e00afb7b782d6b.tar.bz2 |
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.txt | 36 |
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 |