Re: [Qemu-devel] [RFC PATCH v3 4/5] Update documentation for LTTng ust tracing

[Alex Bennée]

address@hidden writes:

> Signed-off-by: Mohamad Gebai <address@hidden>
> ---
>  docs/tracing.txt |   31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
>
> diff --git a/docs/tracing.txt b/docs/tracing.txt
> index bfc261b..64683db 100644
> --- a/docs/tracing.txt
> +++ b/docs/tracing.txt
> @@ -214,6 +214,37 @@ 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. After running Qemu, 
> LTTng
> +should be able to list all available events:
> +
> +    lttng list -u

Running this gives me:

<quote>
UST events:
-------------
None
</quote>

Before or after running qemu. What is the mechanism lttng expects to
find out all these events?

> +
> +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>
> +

The rest of this looks OK and worked on my system.

>  === SystemTap ===
>  
>  The "dtrace" backend uses DTrace sdt probes but has only been tested with


-- 
Alex Bennée