[lttng-dev] tracing program flow
mathieu.desnoyers at efficios.com
Mon May 7 10:53:22 EDT 2012
* Oestman, Fredrik (Fredrik_Oestman at mentor.com) wrote:
> Alexandre Montplaisir wrote:
> > There's a feature on the wishlist to use GCC hooks to automatically
> > generate those probes . The end result would be the same, but it
> > would be much less tedious to do the instrumentation part. A Clang
> > plugin was also mentioned previously , but I don't think anybody has
> > tried it yet.
> Providing functions to GCC containing LTTng tracepoints isn't that
> much of a problem. We found it useful to add the thread ID to the
> trace data provided by GCC so we could keep the threads apart. As far
> as I know, this has to be made in application code at the moment,
> since LTTng can add context trace information only to kernel events at
> the moment.
The "vtid" context is also available in user-space traces. The list of
user-space contexts currently available:
vtid, vpid, pthread_id, procname.
> We also have used the dynamic linker to add LTTng tracepoints to
> memory allocation and de-allocation functions as well as to the
> functions in the ptreads library. It can be done, but overhead is
> Any road-map information for the ability of LTTng to add context
> information to user-space events?
Already available :)
> Fredrik Östman
> lttng-dev mailing list
> lttng-dev at lists.lttng.org
Operating System Efficiency R&D Consultant
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