nx_dstate.nx

nx_dstate.nx -- WHO IS BLOCKED. The D-state (uninterruptible I/O) roster, for the exact moment a box is saturated and every other attribution tool has refused. WHY IT EXISTS, MEASURED 2026-08-14: nx_procchurn returned RED sev=2 with `procs_running=2 procs_blocked=4` and cpu busy=281 permil -- its own note reads "blocked >> running = I/O or lock bound, NOT compute; more CPU would not help". It names the CONDITION and cannot name the PRODUCER. The tool that names producers, nx_ctxtop, then REFUSED: `load_centi=1342 max=800 -- host already saturated`. -- A DIAGNOSTIC WHOSE ADMISSION CEILING IS THE CONDITION IT DIAGNOSES IS UNAVAILABLE EXACTLY WHEN IT IS NEEDED. The refusal is CORRECT (its lib's law: a diagnostic that cannot refuse to run is a load generator with good intentions) -- the gap is that nothing cheap enough to run under saturation exists. WHY THIS ONE CAN RUN WHERE ctxtop CANNOT -- a COST argument, not a wish: nx_ctxtop measures a RATE, and a rate needs TWO samples separated in time: it walks all of /proc TWICE around a 3000 ms window. D-state is a STATE, not a rate, so ONE sample answers it -- one pass, no window, no fork, and /proc/<pid>/stat is a SINGLE small read per pid (ctxtop reads status twice). Roughly half the syscalls and none of the wait. -- A STATE NEEDS ONE SAMPLE; ONLY A DERIVATIVE NEEDS TWO. Paying for a window to answer an instantaneous question is how a cheap question inherits an expensive tool's admission ceiling. ADMISSION IS KEPT, NOT DROPPED, and its ceiling is DERIVED rather than picked: equal marginal impact at half the cost admits at twice the load, so the default is 2x the incumbent's 800. It is POLICY, so it lives in knowledge/dstate.conf and is PRINTED on every run -- a ceiling nobody can see is a magic number wherever it happens to be stored. nx_dstate [conf-path] -- "NOTHING IS BLOCKED" AND "I REFUSED TO LOOK" MUST NEVER SHARE AN OUTCOME, so refusal has its own exit code and its own line. Codes MATCH the sibling (nx_ctxtop): 3 UNMEASURED, 4 REFUSED. exit 0 sampled | 3 UNMEASURED (cannot read /proc) | 4 ADMISSION-REFUSED (load above the ceiling) license_tier: ORIGINAL. Read-only. No hw writes (Rule 26).