Documents profiling instructions that I've figured out over the last
couple of days. Since Rust 1.79, the standard library is compiled with
frame pointers enabled [0]. Grabbing stack-trace information from the
frame pointer makes profiling much easier because the data is just there
in-line. Using debug information (via `dwarf`) is also possible but
requires post-processing of the performance profile with `addr2line`
(`perf script` does that automatically). This can take multiple minutes
or longer, depending on the sampling frequency of the captured
performance data. This makes benchmarking almost infeasible because the
feedback loop is simply too long. Using frame pointers is a much nicer
experience.
The downside is that the application themselves also needs to be
compiled with frame pointers. We achieve that by setting the appropriate
compiler option in `.cargo/config.toml`. Ubuntu [1], Fedora [2] and Arch
[3] also ship all of their code with frame pointers enabled. Also, tech
giants such as Google & Meta have been running their systems with frame
pointers on-by-default for years [4].
[0]:
https://blog.rust-lang.org/2024/06/13/Rust-1.79.0.html#frame-pointers-enabled-in-standard-library-builds
[1]:
https://www.brendangregg.com/blog/2024-03-17/the-return-of-the-frame-pointers.html
[2]: https://pagure.io/fesco/issue/2923
[3]: https://gitlab.archlinux.org/archlinux/rfcs/-/merge_requests/26
[4]:
https://www.brendangregg.com/blog/2024-03-17/the-return-of-the-frame-pointers.html
