dial9: from black box to insight in Tokio

episode 37: dial9: from black box to insight in Tokio.

In this episode of Netstack.fm, Glen talks with Jess Izen and Russell Cohen from Amazon about Dial9, a new tool for understanding what’s happening inside Rust and Tokio applications. They explain how it captures events from different layers of your system and puts them into a single timeline, making it much easier to debug tricky performance issues and unexpected behavior.

They also share how Dial9 came out of real debugging challenges at Amazon, where engineers often had to rely on complex, low level tools. The goal with Dial9 is to make those kinds of insights more accessible, so developers can diagnose problems faster and with less guesswork, while the tool continues to evolve with new features and improvements.

Learn more:

• https://www.youtube.com/watch?v=yTlThfOcslM — TokioConf 2026 - Lightning Talk: dial9: WTF is Tokio actually doing? by Russell Cohen

• https://tokio.rs/blog/2026-03-18-dial9 — Introducing dial9: a flight recorder for Tokio
• https://github.com/dial9-rs/dial9-tokio-telemetry — source code (Tokio Telemetry you can run in production)
• https://github.com/dial9-rs/dial9-tokio-telemetry/blob/main/dial9-trace-format/SPEC.md — trace format spec
• https://www.youtube.com/watch?v=kr0RYMu57kU — demo walkthrough (slightly outdated)
• https://github.com/dial9-rs/dial9-tokio-telemetry/blob/main/dial9-tokio-telemetry/examples/production_use.rs — example

Rama

If you like this podcast you might also like our modular network framework in Rust: https://ramaproxy.org

Chapters

• 00:00 Intro
• 02:01 Meet Russell and Jess
• 05:27 The Mission of the Rust Team at Amazon
• 11:47 Integration with OpenTelemetry and Tracing
• 13:49 The Evolution of Dial 9
• 17:17 Comparing Dial 9 with Existing Tools
• 20:07 Continue exploring history and development and UX of Dial9
• 33:47 Building Self-Serve Solutions
• 36:22 perf sched
• 38:30 Task Dumps
• 41:17 Dial 9: almost a free lunch
• 43:00 Cross-Platform Considerations for Dial 9
• 46:20 Future Features and Improvements for Dial 9
• 50:20 Dial 9 usage today
• 54:31 Considerations before using Dial 9
• 01:03:05 Getting Started with Dial 9
• 01:05:30 Outro

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Music for this episode was composed by Dj Mailbox. Listen to his music at https://on.soundcloud.com/4MRyPSNj8FZoVGpytj