bench: mono-vs-vdisp micro-benchmark + revised Decision 11 rationale

Hypothesis-driven measurement of "did monomorphisation actually buy us performance?" on a 100M-iter LCG hot loop, AILang mono'd code vs. four C reference variants (direct-inlinable, direct- noinline, indirect-monomorphic, indirect-polymorphic). Zen 3, clang -O2, median-of-15. Headline: H1 supported, but the mechanism is inlining, not dispatch shape. AILang mono = hand-C direct (1.000x). Indirect- monomorphic = direct-noinline (1.000x) — saturating branch predictor makes the indirect-call cost vanish on this hardware. Inlining is the actual 3.31x win; polymorphic indirect adds another 21% predictor-miss penalty. DESIGN.md Decision 11 gains a rationale paragraph reframing mono as inlining-enabler rather than indirect-call-eliminator, with explicit pointer to the bench. JOURNAL entry records the full methodology, ratios, limitations, and the side-effect mono-pass env.globals-seeding bug surfaced while building the AILang fixture (separate RED-first debug iter to follow).
2026-05-10 01:03:21 +02:00
parent 105ad3fe80
commit 4cacfcbdac
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