Yeah, as far as I know, perf [1] is successfully using libunwind to provide callstacks. Probably, LTTng team should think about it too, if there are no serious obstacles.
[1]: https://perf.wiki.kernel.org/index.php/Main_Page Best regards, Valentin Grigorev On Thu, Mar 26, 2020 at 11:53 PM Milian Wolff <milian.wo...@kdab.com> wrote: > On Donnerstag, 26. März 2020 20:41:17 CET Mathieu Desnoyers via lttng-dev > wrote: > > ----- On Mar 26, 2020, at 1:39 PM, lttng-dev <lttng-dev@lists.lttng.org> > > wrote: > > > 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 > too? > > > 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 > wrt > > 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 > customers > > showing interest in getting this done. > > libunwind [1] should meet the requirements you need. It is high > performance > thanks to extensive caching, signal safe and does not rely on frame > pointers. > > [1]: https://github.com/libunwind/libunwind > > -- > Milian Wolff | milian.wo...@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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