vllm:request_prefill_kv_computed_tokens

Histogram of new KV tokens computed during prefill, excluding cached tokens.

MetricPrometheusvLLM v0.23.0verified 10 hr ago

Identity

Prometheus type: histogram
Labels: model_nameengine
Buckets: Not recorded — bucket boundaries are computed at runtime from max_model_len, so no fixed values are true
Unit: Not recorded — vLLM registration code has no structured unit field, and units are not inferred from name suffixes

Semantic coverage

covered · Availability & namecovered · Structural identitycovered · Measurement semanticscovered · Causal/runtime semanticscovered · Interpretation & compositioncovered · Guarded guidance

Metric knowledge (6)

Claim	Semantic layer	Verified
In vLLM v0.23.0, `vllm:request_prefill_kv_computed_tokens` observes one histogram sample per finished request: prompt tokens minus non-negative cached tokens.	Measurement semantics	10 hr ago
In vLLM v0.23.0, `vllm:request_prefill_kv_computed_tokens` is computed in finished-request logging after request completion from `num_prompt_tokens` and `num_cached_tokens`.	Causal/runtime semantics	10 hr ago
In vLLM v0.23.0, `vllm:request_prefill_kv_computed_tokens` measures newly computed prefill KV work per completed request, not total prompt length when caching contributes.	Interpretation & composition	10 hr ago
In vLLM v0.23.0, `vllm:request_prefill_kv_computed_tokens` compare distributions under matched workloads; use cached-token counters as companions and do not treat one bucket count as token throughput.	Guarded guidance	10 hr ago
In vLLM v0.23.0, `vllm:request_prefill_kv_computed_tokens` is registered as a Prometheus histogram.	Structural identity	10 hr ago
In vLLM v0.23.0, `vllm:request_prefill_kv_computed_tokens` is registered with the label names `model_name`, engine.	Structural identity	10 hr ago

Related Use Cases (1)

#40696: Full-block eligibility creates prefix-cache cliffs

Availability

vllm:request_prefill_kv_computed_tokens is registered as a Prometheus histogram in vLLM v0.23.0.

vllm.surface.prometheus_metricscomplete_inventoryPrometheusStatLogger metrics publisher

vLLM v0.23.0 v1 metrics loggers.py · vllm/v1/metrics/loggers.py:920-931