[lttng-dev] LTTng user-space callstacks
valentin.grigorev at jetbrains.com
Fri Mar 27 09:44:19 EDT 2020
Yeah, as far as I know, perf  is successfully using libunwind to provide
callstacks. Probably, LTTng team should think about it too, if there are no
On Thu, Mar 26, 2020 at 11:53 PM Milian Wolff <milian.wolff at kdab.com> wrote:
> On Donnerstag, 26. März 2020 20:41:17 CET Mathieu Desnoyers via lttng-dev
> > ----- On Mar 26, 2020, at 1:39 PM, lttng-dev <lttng-dev at lists.lttng.org>
> > > Hello!
> > >
> > > Currently, callstack collection in LTTng is only available for
> > > kernel-space
> > > events with context fields callstack-kernel and callstack-user .
> > >
> > > Is it expected that callstack collection for LTTng-UST will be added
> > > And if it is expected, then how soon?
> > Hi Valentin,
> > It is something that would be interesting and useful, but a lot of work
> > would be needed to have stack-walking this is fast enough and reentrant
> > signal handlers. Unfortunately, the backtrace(3) functions do not meet
> > those requirements.
> > Also, for gathering user-space callstacks from the kernel tracer, it only
> > works if all user-space is compiled with frame pointers. This is also a
> > limitation that would require a lot of work to overcome neatly.
> > None of those features are currently on any roadmap due to lack of
> > showing interest in getting this done.
> libunwind  should meet the requirements you need. It is high
> thanks to extensive caching, signal safe and does not rely on frame
> : https://github.com/libunwind/libunwind
> Milian Wolff | milian.wolff at kdab.com | Senior Software Engineer
> KDAB (Deutschland) GmbH, a KDAB Group company
> Tel: +49-30-521325470
> KDAB - The Qt, C++ and OpenGL Experts
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