Tokio 3.0 Brings Structured Concurrency and 40% Throughput Gains

TL;DR

Tokio 3.0 introduces structured concurrency with scoped tasks, new work-stealing scheduler, and 40% throughput improvement on 32+ core systems.

Key Findings

• Structured concurrency: scoped tasks guarantee child task completion before parent exits

• 40% throughput gain on 32-core benchmarks via improved work-stealing scheduler

• Breaking change: tokio::spawn requires task to be Send — eliminates common runtime panics

• io_uring backend now stable on Linux 5.15+ for async I/O

Key Terms