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All versions · Version range: v0.23.0

In vLLM v0.23.0, vllm:kv_cache_usage_perc is a Prometheus gauge for KV-cache usage where 1 means 100 percent usage.

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

Metric

kv_cache_usage_perc

Applies when

PrometheusStatLogger metrics publisherV1 metrics

Evidence

vLLM v0.23.0 v1 metrics loggers.py(vllm/v1/metrics/loggers.py:519-527)
definesprimarysource_codecode_introspection

Open cited lines in immutable upstream source ↗

519:         gauge_kv_cache_usage = self._gauge_cls(
520:             name="vllm:kv_cache_usage_perc",
521:             documentation="KV-cache usage. 1 means 100 percent usage.",
522:             multiprocess_mode="mostrecent",
523:             labelnames=labelnames,
524:         )
525:         self.gauge_kv_cache_usage = create_metric_per_engine(
526:             gauge_kv_cache_usage, per_engine_labelvalues
527:         )

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

  • how much free KV cache remains for a specific model
  • whether a workload will preempt
  • a universal alert threshold

Guards

  • vllm_version = v0.23.0
  • metric_name = vllm:kv_cache_usage_perc
  • runtime_component = scheduler

Freshness

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