2026-09-26 20:42:22 +00:00
1 changed files with 9 additions and 2 deletions
@@ -131,8 +131,15 @@
  Criterion bench itself, old and new as separate binaries run alternately
  (3 rounds), agrees except for `ObjectHeader::parse`, which it puts about
  7% slower (25.9 vs 24.1 µs for 401 headers) while the listing that
-  parses those headers is 5–8% faster; that one remains unexplained and is
-  to be rechecked on an idle machine.
+  parses those headers is 5–8% faster. **Rechecked on an idle tank
+  (2026-09-26, load 1.95 at the start, 3–4 during; Criterion, `main`
+  `479d8b4` vs this branch `b49ec39` as separate binaries, 2 alternating
+  rounds):** `ObjectHeader::parse` for 401 headers 24.0–24.1 µs → 25.5–25.8
+  µs (+6–7%, about 4 ns per header — real, not noise); symbol-table nodes
+  2.39 → 1.94–2.04 µs (−17%); group B-tree walk 405–411 → 322–351 ns
+  (−16%); listing the 400-group file through the facade 8.56–8.71 →
+  8.40–8.42 ms (−2.4%). Net, local metadata reads are slightly faster; the
+  per-header cost is a known, small regression.
 - New equivalence harness `clawhdf5-format/tests/storage_equivalence.rs`:
  every converted parser runs over the file as a slice and over
  `storage::CountingStorage` — a `Storage` that serves an in-memory buffer