nx_bench_companion.nx

nx_bench_companion.nx -- substrate-honest measurement primitive for parallel-companion scenarios. Captures EVERY measurable axis from a running [[nx_session]] into one structured report. Designed for substrate-internal counters (deterministic + paired) so qemu-riscv64 produces meaningful comparison numbers BEFORE the physical-hardware run lands. Per CARDINAL [[feedback-no-strawman-perf-comparisons]]: this primitive emits ONLY measured counters from real substrate calls. No throughput ratio is claimed without paired measurement of the SAME workload on the SAME substrate (e.g. nx_actor_role_llm v1 vs v2; or future Nishi vs llama.cpp on identical Llama-7B Q4_K). V1 ships the counter-tabulation primitive + the report struct. V2 will add the run-N-iterations loop that drives a session through multiple cycles and accumulates the deltas. V3 will add TSV emission via nx_runtime fact stream for cross-session comparison.