Feature Request: Ability to track deep recursion using frame pointers.

[hargoniX]

In programs with very deep recursion samply begins producing flamegraphs that are "chopped apart" like in the below picture:

(Link to profile: https://share.firefox.dev/49aeiVw)
The majority of these calls are in fact not happening at the same stack depth but are instead part of a very deep recursion in the profiled program. Even setting kernel.perf_event_max_stack to a high value does not help in this situation.

perf together with a perf.data visualizer like flamegraph.pl on the other hand, can make use of the framepointer that is included in this build of the binary to produce a more accurate flamegraph:

And then futher up:

It would be very nice if samply provided an option to track deep recursion. Presumably using framepointers as the current approach appears to be unable of doing this?

[ishitatsuyuki]

FWIW you can perf record then load the resulting perf.data into Firefox Profiler UI with samply load perf.data. This should give you a decent workaround in the meantime.

samply does support kernel-provided stacks but it's not exposed right now. Ideally we should make more of perf_event_attr we pass to the kernel configurable.