10ba02e341
We appear to have caused a pretty big performance regression (~40%) in037a2e64b6(identified through `git-bisect`). Specifically, the regression appears to have been caused by [`aef411a` (#7605)](aef411abf5). Weirdly enough, undoing just that on top of `main` doesn't fix the regression. My hypothesis is that using the same file descriptor for read AND write interests on the same runtime causes issues because those interests are occasionally cleared (i.e. on false-positive wake-ups). In this PR, we spawn a dedicated thread each for the sending and receiving operations of the TUN device. On unix-based systems, a TUN device is just a file descriptor and can therefore simply be copied and read & written to from different threads. Most importantly, we only construct the `AsyncFd` _within_ the newly spawned thread and runtime because constructing an `AsyncFd` implicitly registers with the runtime active on the current thread. As a nice benefit, this allows us to get rid of a `future::select`. Those are always kind of nasty because they cancel the future that wasn't ready. My original intuition was that we drop packets due to cancelled futures there but that could not be confirmed in experiments.
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
releaseprofile. sudo 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.