Principles for Fast Tokio Applications

The article outlines best practices for optimizing Tokio async applications, emphasizing that performance depends on specific workload contexts and requires balancing fairness with batching and isolation. Key principles include first determining whether a performance problem actually exists by working backward from real metrics, as many apparent issues may not meaningfully impact user-facing outcomes. The guide covers strategies like splitting work for latency optimization, batching to amortize overhead, careful mutex management, and constraining parallelism, while noting that debugging tools like dial9 often reveal the real bottleneck lies in application code rather than Tokio itself.