mirror of
https://github.com/rustfs/rustfs.git
synced 2026-07-27 00:38:16 +00:00
houseme
ce7d3119b2
`MetricsCollector::record_io_operation` recomputed P50/P95/P99 on every disk IO by taking a read lock, collecting up to `max_latency_samples` (1000) into a `Vec<u128>` and fully sorting it — an O(n log n) alloc+sort per operation on the GET read path (gated by stage metrics). Both consumers sample only periodically: the autotuner reads `avg_io_latency_us` on its tuning tick, and the P95/P99 values are never read internally — they only feed OTEL export. Nothing needs per-IO freshness. Split the two costs: - The window mean (stored in `avg_io_latency_us`, read by the autotuner) is now maintained in O(1) via a running sum kept in step with the window's push/pop, and refreshed on every op — no sort, no warm-up regression. - The P95/P99 sort is throttled to once per `PERCENTILE_RECOMPUTE_INTERVAL` (128) operations. A bounded lag is invisible to the periodic autotuner tick and OTEL export while the per-op sort cost is amortised ~128x away. Semantics are otherwise unchanged: same sliding window, same percentile indices, same mean value. Tests updated — the percentile test forces a recompute to exercise the math directly, and a new test asserts the mean tracks every op while the percentiles only recompute at the interval boundary. Addresses rustfs/backlog#1185 (P1). Co-authored-by: heihutu <heihutu@gmail.com>