nx_linkqual_cycles.nx

nx_linkqual_cycles.nx -- CYCLE-ACCURATE hot-path measurement of the link-quality substrate using the sovereign __rdtsc() intrinsic. This is the hardware-limit metric: reference-cycles per op straight off the CPU's timestamp counter, with NO per-op syscall in the loop (two reads bracket N calls, amortized). HONEST METHOD: - a warmup pass is discarded (caches/branch-predictors warm). - inputs vary per-iteration so the work can't be constant-folded. - rdtsc measures INVARIANT-TSC reference cycles (the constant base-rate counter), NOT turbo-scaled retired core cycles -- so we ALSO bracket the identical loop with the microsecond clock and derive the effective TSC GHz (cycles/ns). If that GHz matches the CPU's base clock, the two independent clocks agree and the numbers are trustworthy (1:1 cross- validation, [[feedback-1to1-proof-no-proxy-2026-05-28]]). license_tier: ORIGINAL