tracing

Seven spans from arrival to the last token, with realistic durations for each. The three places latency hides that a naive trace misses entirely, why the decode phase is one span and not four hundred, and the attribute that explains most tail latency in a single field.

GPU utilization at 100% tells you nothing, and a trace per token would cost more than the tokens. The span layout for one request, the GPU counters that read headroom, the cardinality budget that keeps the metrics store alive, and cost attribution that charges tenants for the batch share they used.