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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
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Rust development guide
Firezone uses Rust for all data plane components. This directory contains the Linux and Windows clients, and low-level networking implementations related to STUN/TURN.
We target the last stable release of Rust using rust-toolchain.toml.
If you are using rustup, that is automatically handled for you.
Otherwise, ensure you have the latest stable version of Rust installed.
Reading Client logs
The Client logs are written as JSONL for machine-readability.
To make them more human-friendly, pipe them through jq like this:
cd path/to/logs # e.g. `$HOME/.cache/dev.firezone.client/data/logs` on Linux
cat *.log | jq -r '"\(.time) \(.severity) \(.message)"'
Resulting in, e.g.
2024-04-01T18:25:47.237661392Z INFO started log
2024-04-01T18:25:47.238193266Z INFO GIT_VERSION = 1.0.0-pre.11-35-gcc0d43531
2024-04-01T18:25:48.295243016Z INFO No token / actor_name on disk, starting in signed-out state
2024-04-01T18:25:48.295360641Z INFO null
Benchmarking on Linux
The recommended way for benchmarking any of the Rust components is Linux' perf utility.
For example, to attach to a running application, do:
- Ensure the binary you are profiling is compiled with the
benchprofile. sudo perf perf record -g --freq 10000 --pid $(pgrep <your-binary>).- Run the speed test or whatever load-inducing task you want to measure.
sudo perf script > profile.perf- Open profiler.firefox.com and load
profile.perf
Instead of attaching to a process with --pid, you can also specify the path to executable directly.
That is useful if you want to capture perf data for a test or a micro-benchmark.