bench: real black_box barrier + three-signal growth-curve gate

Adds el_black_box (inline asm, +r constraint, memory clobber) and
runtime/elbench.el: a growth-curve classifier that gates time AND
allocation-count AND allocation-bytes, failing if any exceeds its
declared curve.

Refusal is a first-class verdict. The classifier REFUSES rather than
classifying when the largest measurement is below the floor, or when a
series is hard-flat across an 8x input range -- the shape produced when
the optimiser deletes the work. Reporting O(1) there would be a
confident answer with nothing behind it. Disagreeing ratios report
INDETERMINATE rather than a guess.

Deviation from DESIGN.md 6.2, stated in the source: uses consecutive
ratios on a mandated geometric sweep rather than least-squares over
candidate curves. Ratios are directly interpretable on a doubling sweep
and need no floating point; the cost is weaker O(n) vs O(n log n)
separation, reported as an ambiguous band rather than guessed.

Documents the counter scope limit: engram_*.c and libcurl malloc are
NOT tracked, so a flat curve over engram/HTTP-dominated work is not
evidence of anything.

13 tests prove the classifier against real measured series from
fitprobe.el -- including that an accumulator's allocation COUNT is
linear while its bytes are quadratic, and that el #132's pure-CPU shape
reads FLAT on both allocation signals and is caught only by time.

This commit is contained in:

Neuron

2026-08-15 21:45:13 -05:00

parent b5d1e53902

commit 6a6b589ba0

5 changed files with 397 additions and 0 deletions

									
										lang/runtime/el_runtime.h
									
		+1
		
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				@@ -1022,6 +1022,7 @@ el_val_t  el_mem_check(void);

				el_val_t  el_alloc_count(void);

				el_val_t  el_alloc_bytes(void);

				el_val_t  el_peak_rss(void);

				el_val_t  el_black_box(el_val_t v);

				/* Semantic retrieval surface. NOT interchangeable with engram_search_json,

				 * which is lexical by design — see the note at the definition. */