[edwintorok]

You probably already know, but with OCaml 5 the only way to get flamegraphs working is to either:

* use framepointers [1]

* use LBR (but LBR has a limited depth, and may not work on on all CPUs, I'm assuming due to bugs in perf)

* implement some deep changes in how perf works to handle the 2 stacks in OCaml (I don't even know if this would be possible), or write/adapt some eBPF code to do it

OCaml 5 has a separate stack for OCaml code and C code, and although GDB can link them based on DWARF info, perf DWARF call-graphs cannot (https://github.com/ocaml/ocaml/issues/12563#issuecomment-193...)

If you need more evidence to keep it enabled in future releases, you can use OCaml 5 as an example (unfortunately there aren't many OCaml applications, so that may not carry too much weight on its own).

[1]: I haven't actually realised that Fedora39 has already enabled FP by default, nice! (I still do most of my day-to-day profiling on an ~CentOS 7 system with 'perf record --call-graph dwarf -F 47 -a', I was aware that there was a discussion to enable FP by default, but haven't noticed it has actually been done already)

[namibj]

No, LBR is an Intel-only feature.

[edwintorok]

https://www.phoronix.com/news/AMD-Zen-4-LbrExtV2 LBR is supposed to work on AMD too, except it doesn't. I'll have to open a bug report (it records the data, it just can't parse it afterwards)