Records the bench numbers (rc/bump 2.5–2.9x on the Implicit-mode
fixtures, missing Decision 10's 1.3x retirement target) and the
two paths forward — lower the threshold (Path A, pragmatic; rc
and gc are within 5% of each other so retirement under "RC ≤
Boehm ± 5%" qualifies) vs build a slab/pool allocator first
(Path B, larger iter, closes most of the gap to bump).
The 1.3x criterion was orchestrator-level commitment in
Decision 10 and not meeting it is a prompt for an orchestrator-
level discussion, not for the implementer to autonomously flip
the default. 18f deliberately stops without flipping default,
without dropping -lgc, without marking Decision 9 historical.
Brummel
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