* perf(metrics): drop needless per-emission work on hot metric paths
Audit of the metrics hot paths surfaced four low-risk wins where emission did
work it did not need to:
- `record_file_cache_reclaim_success/error` (disk/local.rs) called `.to_string()`
on `kind` (already `&'static str`) and on the `"ok"`/`"err"` literals, heap-
allocating up to four `String`s per page-cache reclaim window — which runs per
read-stream reclaim. The `metrics` macros accept `&'static str` label values
directly, so pass them as-is.
- `record_read_repair_dedup` (set_disk/core/io_primitives.rs) likewise
`.to_string()`-ed an already-`&'static str` `reason`.
- `SetDisks::get_object_reader` (set_disk/ops/object.rs) captured `Instant::now()`
and emitted the `rustfs.lock.acquire.*` counter and histogram unconditionally
on every GET, right beside an already-gated stage timer. Gate them behind
`get_stage_metrics_enabled()` too, so an inactive observability config pays no
per-GET clock read or recorder lookups.
- The per-response-body-chunk counter in server/http.rs re-ran the `counter!`
registry lookup on every chunk (a streamed GET emits many). Resolve the
label-less handle once into a `LazyLock<metrics::Counter>`; the global recorder
is installed at startup before any response streams, so the cached handle binds
to the final recorder.
No metric names or label values change. The only behavior change is that the
`rustfs.lock.acquire.*` GET-path metrics now follow the GET stage-metrics flag,
consistent with the neighbouring stage timings.
Co-Authored-By: heihutu <[email protected]>
* perf(metrics): gate page-cache reclaim metrics behind metrics_enabled()
`record_file_cache_reclaim_success/error` run per read-stream reclaim window on
large-object reads and emitted unconditionally. When general metrics are
disabled the `counter!`/`histogram!` macros still construct three metric keys
per call for nothing. Skip the emission behind `rustfs_io_metrics::metrics_enabled()`,
matching how the io-metrics free functions self-gate. The serial reclaim-metrics
test now enables the flag (save/restore) alongside the existing stage gate.
Left ungated deliberately: `record_read_repair_dedup` (rare read-repair path,
and its non-serial test would need a global-flag toggle), and the HTTP body-chunk
counter (its cached handle already makes the disabled case a no-op increment).
Co-Authored-By: heihutu <[email protected]>
---------
Co-authored-by: heihutu <[email protected]>
