ordo-one/swift-parca

`swift-parca` supports continuous low-overhead profiling of Swift Server applications at scale, for always-on tracking of performance issues in production.

Sample output

Example of reviewing `swift-build` stacks

Example of `swift-nio` benchmark

🚀 Getting Started

swift-parca is provided as a single, pre-configured Docker container image that bundles Parca and all necessary dependencies, to simplify profiling of Swift applications at scale.

To begin profiling your Swift application, follow these simple steps:

Start the Parca Server

Use the provided docker-compose.yml to bring up the Parca server:

docker compose up -d

This starts the Parca server, listening on HTTP port 7070 for UI and profiling data from agents.

Start the Parca Agent

On each server running your Swift workloads, deploy the parca-agent:

export REMOTE_STORE_ADDRESS=<PARCA_SERVER_IP>:7070
docker-compose -f docker-compose.agent.yml up -d

Documentation

For further setup and usage instructions, please refer to the Parca Documentation.

Performance Overhead

Parca agent samples 19 times per second per core, only the stack addresses are aggregated in eBPF maps; the rest of the processing is sending them and binaries to the server, where demangling/symbolicatition happens on demand when a trace is viewed. In practice this results in neglible overhead on the profiled application, that can be sub 1%.

Background

Parca normally uses a Go demangler which lacks Swift symbol demangling.

This project addresses this limitation by configuring Parca to delegate address-to-line lookups and symbol demangling to a custom swift-addr2line embedded tool. This tool leverages the native Swift runtime function for demangling, ensuring accurate and human-readable stack traces, while relying on a Rust-based gimli addr2line (or to llvm-addr2line) for actual address lookup.

This direct access of the native Swift runtime function is needed until SE-262 is formally integrated into the standard library.

Using llvm-addr2line

If you want to use llvm-addr2line instead of the gimli-rs/addr2line, uncomment the line containing apt-get install -y llvm-19 in the Dockerfile.

This installs the LLVM tools, making the binary available at /usr/bin/llvm-addr2line-19.

Then you need to update the docker-compose.yml environment:

    environment:
      - ADDR2LINE_PATH=/usr/bin/llvm-addr2line-19

Requirements

The container is packaged for Linux x86_64 and ARM64. It is possible to run entirely under a Linux VM (with kernel 5.4+) under Apple sillicon.

Package Metadata

Repository: ordo-one/swift-parca

Default branch: main

README: README.md