OpenTelemetry's metrics performance has long been a sore point for high-throughput users. Recording a simple Counter with three attributes/labels cost around 50 nanoseconds per call - enough to show up in CPU profiles and rule OpenTelemetry out of the busiest code paths.

Pre-resolved metric handles are an old answer. Prometheus client libraries expose labelled-metric handles you can cache, and Windows Performance Counters have used the same pattern for decades. OpenTelemetry now offers it as a first-class API, called bound instruments, and on that same hot path, recording drops to under 2 nanoseconds - roughly 25× faster (Measured in OTel Rust Sdk)

This lightning talk shows where the speedup comes from, when to reach for it (high-frequency counters with a fixed, known attribute set), and - more importantly - when not to. Used the wrong way, the new fast path can be slower than the original.

Flexible by default, fast when you need it.