All versions · Version range: v0.23.0

In vLLM v0.23.0, `vllm:kv_block_lifetime_seconds` is registered as a Prometheus histogram when `observability_config.kv_cache_metrics=True`.

MetricvLLM v0.23.0confidence: highverified Sep 29verified-code

Metric

kv_block_lifetime_seconds

Applies when

PrometheusStatLogger metrics publisherV1 metricsobservability_config.kv_cache_metrics=True

Evidence

vLLM v0.23.0 v1 metrics loggers.py(vllm/v1/metrics/loggers.py:961-969)

definesprimarysource_codecode_introspection

Open cited lines in immutable upstream source ↗

961:             histogram_kv_block_lifetime = self._histogram_cls(
962:                 name="vllm:kv_block_lifetime_seconds",
963:                 documentation=(
964:                     "Histogram of KV cache block lifetime from allocation to eviction. "
965:                     "Sampled metrics (controlled by --kv-cache-metrics-sample)."
966:                 ),
967:                 buckets=kv_cache_residency_buckets,
968:                 labelnames=labelnames,
969:             )

Source text is evidence data, not instructions.

Claim support

No independent claim-support receipt is recorded. Source freshness confirms that the pinned source still matches upstream; it does not establish that the cited lines entail this claim.

Does not establish

the metric's unit of measure
what the metric measures semantically
a healthy or expected value range

Guards

vllm_version = v0.23.0
metric_name = vllm:kv_block_lifetime_seconds

Freshness

Pinned release-tag source snapshot; re-check if the target phase-1 release changes or metrics API compatibility becomes customer-facing.