In vLLM v0.23.0, `prefill_time` is computed as `req_stats.first_token_ts` - `req_stats.scheduled_ts`; the source comment describes the prefill interval as from first `SCHEDULED` to first `NEW_TOKEN` and says any preemptions during prefill are included in the interval.

MetricvLLM v0.23.0confidence: highverified 2 hr agoverified-code

V1 metricsIterationStats.update_from_finished_request finished-request accounting

vLLM v0.23.0 v1 metrics stats.py(vllm/v1/metrics/stats.py:442-444)

definesprimarysource_codecode_introspection

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

In vLLM v0.23.0, prefill_time is computed as req_stats.first_token_ts - req_stats.scheduled_ts; the source comment describes the prefill interval as from first SCHEDULED to first NEW_TOKEN and says any preemptions during prefill are included in the interval.