Files
DarkRoom/core/dr-inference-engine/src/lib.rs
T
dtourolle c73743394f Add a CoreML rung on macOS
The macOS ladder was the CPU provider alone, with CoreML listed as a gap.
It is now CoreML, then the CPU, then tract — unmeasured, since nobody here
has a Mac, and safe to ship unmeasured because the probe's clock rejects a
CoreML slower than the CPU and `attempt` refuses one that crashes.

- `Rung::CoreMl`, a compiling rung like TensorRT: an ML Program with every
  compute unit allowed, falling back to the CPU until each model's program
  is built. The embedder stays on the CPU, as on the Hexagon (§7).
- The cache is one directory per model and runtime version. CoreML keys a
  model committed from memory on its input and node names, not its
  weights (ONNX Runtime 1.29, coreml_execution_provider.cc), so two
  exports of one architecture would otherwise share a program.
- The fingerprint on macOS is the chip and the OS release, which ships
  CoreML.
- The desktop looks for the runtime in the bundle's Contents/Frameworks
  and Homebrew's prefixes; fetch-desktop-runtime.sh on a Mac downloads
  ONNX Runtime 1.29.0 for Apple silicon, which carries CoreML.

docs/dev/macos.md says what exists, how to build it, and which log lines
to ask a Mac user for.
2026-10-03 16:50:37 -04:00

714 lines
25 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
//! Which runtime, which provider and which model form — decided once per
//! device, and the only crate that knows the answer (docs/dev/inference.md).
//!
//! Consumers ask for a session by [`Role`] and get `ort`'s `Session` back;
//! what built it — tract on one core, ONNX Runtime's CPU pool, a TensorRT
//! engine, a MIGraphX program, the Hexagon — is this crate's business and
//! shows up in [`status`] for the settings row and nowhere else.
//!
//! The shape follows §3 of the spec: `ort` links nothing (`alternative-backend`),
//! and the first call hands it an API table from either a `libonnxruntime`
//! found on disk or from `tract`. That choice is once per process, because
//! `ort::set_api` is; everything after it — which provider, whether an engine
//! has been compiled yet — is per session and may change between two calls.
use std::collections::{BTreeSet, HashMap};
use std::path::{Path, PathBuf};
use std::sync::{Arc, Mutex, MutexGuard, OnceLock};
use std::time::{Duration, Instant};
use serde::{Deserialize, Serialize};
mod api;
mod engines;
mod probe;
mod session;
pub use api::Runtime;
pub use ort::session::Session;
/// What a model is for. The role fixes the precision rule (§7): an embedder
/// runs in f32 on every rung, a detector may run in fp16 or int8.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum Role {
Detector,
Embedder,
Segmenter,
Scene,
/// The dense landmark model behind the eye reading (docs/dev/faces.md §7c).
Landmarks,
/// The eye-state and sunglasses classifiers, a few hundred kilobytes.
EyeClassifier,
/// XFeat, the panorama keypoint detector (docs/dev/panorama.md).
Keypoints,
/// MI-GAN, the panorama border filler (docs/dev/panorama.md §12). Plain
/// convolutions, so any rung serves it; fp16 on TensorRT and int8 on
/// the Hexagon are the point of it.
Inpainter,
/// The learned demosaic and denoise on the raw mosaic (docs/dev/denoise.md).
/// fp16 costs it nothing measurable; int8 costs 6–9 dB, because 256
/// levels cannot hold the shadow steps it exists to recover — so the
/// Hexagon does not take it.
Denoiser,
}
/// Which numeric form of a model a session was built from.
///
/// `Int8` is a different network from `F32` for a detector — it finds a
/// different set of faces — which is why [`form_suffix`] exists and why a
/// caller appends it to `model_id`.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum Form {
F32,
Int8,
}
/// A rung of the ladder (§2). Ordered: a user override names the highest rung
/// the probe may take, and a compiling rung falls back to the one below it
/// until its engine exists. The order is within a vendor's ladder — a
/// machine has NVIDIA rungs or an AMD rung, never both — so a ceiling is
/// read as "no higher than this on whichever ladder the device has".
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, Serialize, Deserialize)]
pub enum Rung {
/// ONNX Runtime's CPU provider, or tract when no runtime file was found.
Cpu,
/// NVIDIA, through the CUDA provider. Desktop only.
Cuda,
/// NVIDIA, through a TensorRT engine compiled on this device. Desktop only.
TensorRt,
/// AMD, through a MIGraphX program compiled on this device. Desktop
/// only. ONNX Runtime's ROCm provider, the CUDA provider's twin, was
/// removed in ONNX Runtime 1.23, so there is no non-compiling AMD rung
/// to fall back to: this one falls back to the CPU.
MiGraphX,
/// Qualcomm's Hexagon NPU through QNN, int8 models only. Android only.
Hexagon,
/// Apple, through CoreML: the Neural Engine, the GPU or the CPU, as
/// CoreML schedules it. macOS only. Compiles an ML Program per model on
/// first use, so it is a compiling rung with the CPU below it. The
/// embedder stays on the CPU, as on the Hexagon: the Neural Engine
/// computes in fp16 (§7).
CoreMl,
}
impl Rung {
pub fn label(self) -> &'static str {
match self {
Rung::Cpu => "CPU",
Rung::Cuda => "CUDA",
Rung::TensorRt => "TensorRT",
Rung::MiGraphX => "MIGraphX",
Rung::Hexagon => "Hexagon NPU",
Rung::CoreMl => "CoreML",
}
}
/// The rung a request lands on while this one's engine is still being
/// compiled (§6 step 2).
fn fallback(self) -> Rung {
match self {
Rung::TensorRt => Rung::Cuda,
Rung::MiGraphX | Rung::Hexagon | Rung::CoreMl | Rung::Cuda | Rung::Cpu => Rung::Cpu,
}
}
/// Whether a session on this rung needs an engine built first.
fn compiles(self) -> bool {
matches!(
self,
Rung::TensorRt | Rung::MiGraphX | Rung::Hexagon | Rung::CoreMl
)
}
/// The model form this rung wants for a role.
fn form(self, _role: Role) -> Form {
match self {
Rung::Hexagon => Form::Int8,
_ => Form::F32,
}
}
/// Whether this rung runs `role` at all. The Hexagon takes int8 graphs
/// only, and the embedder is never int8 (§7) — it runs on the CPU
/// beside a detector on the NPU, so its vectors compare across devices.
/// Nor is the denoiser: its int8 form failed the 0.5 dB gate by 6–9 dB
/// (denoise.md §8), so it runs on the CPU there too. CoreML is kept off
/// the embedder for the same reason as the Hexagon: the Neural Engine is
/// fp16, and which unit runs a graph is CoreML's choice.
fn serves(self, role: Role) -> bool {
match self {
Rung::Hexagon => !matches!(role, Role::Embedder | Role::Denoiser),
Rung::CoreMl => role != Role::Embedder,
_ => true,
}
}
}
/// How long a session outlives its last use unless [`Config::decay`] says
/// otherwise: long enough for the next click, short enough that a session's
/// GPU or NPU memory does not sit under the develop view for long.
pub const DEFAULT_DECAY: Duration = Duration::from_secs(30);
/// What [`init`] is told once, at launch.
#[derive(Clone, Debug, Default)]
pub struct Config {
/// Where to look for `libonnxruntime`, in order. An empty path means "the
/// bare library name through the system loader", which is how the APK's
/// own copy is found on Android.
pub runtime_dirs: Vec<PathBuf>,
/// Probe cache and compiled engines (§4, §5). Disposable.
pub cache_dir: PathBuf,
/// The canonical model files on this device, so engines can be compiled
/// ahead of the first request for them.
pub models: Vec<(Role, PathBuf)>,
/// Models compiled into the binary, for the same reason.
pub embedded: Vec<(Role, &'static [u8])>,
/// The highest rung the user allows; `None` is "the best that works".
pub ceiling: Option<Rung>,
/// ONNX Runtime's intra-op pool; 0 picks from the core count.
pub threads: usize,
/// How long an unused session stays loaded. Zero means the default.
pub decay: Duration,
}
/// One line for the settings row, and the numbers behind the progress row.
#[derive(Clone, Debug)]
pub struct Status {
pub runtime: Runtime,
/// The rung selected, or the floor while the probe is still running.
pub rung: Rung,
/// Why — "probe passed", or the failure that demoted the rung above.
pub reason: String,
pub probing: bool,
/// Engines compiled and engines wanted, for a compiling rung; `(0, 0)`
/// otherwise.
pub engines: (usize, usize),
/// Every rung above the selected one that was tried, and why it lost.
pub failed: Vec<(Rung, String)>,
}
impl Status {
/// "Hexagon NPU · int8 · ONNX Runtime 1.29" — the settings row's text.
pub fn line(&self) -> String {
let form = match self.rung {
Rung::Hexagon => " · int8",
Rung::TensorRt | Rung::MiGraphX => " · fp16",
_ => "",
};
format!("{}{} · {}", self.rung.label(), form, self.runtime.label())
}
}
/// A model the caller can run, whatever is or is not loaded right now.
///
/// Holds the bytes, not a session. [`Model::acquire`] finds the loaded copy
/// in the registry — shared with every other holder of the same model —
/// or loads one, and every acquire refreshes the copy's last-used time.
/// The reaper unloads anything idle for [`Config::decay`]; a scan that runs
/// the detector on every image never lets it go idle, a click in the
/// develop view lets the segmenter go after a quiet spell, and a handle
/// used again after that simply loads again. Nobody states a policy.
///
/// The registry key includes the rung, so a reload after a compiled engine
/// has landed moves up to it by itself (§6 step 4).
pub struct Model {
role: Role,
form: Form,
bytes: Arc<[u8]>,
/// `engines::hash` of the bytes, taken once: an acquire per tile of a
/// border fill must not hash 28 MB each time.
hash: u64,
}
/// A loaded session, held for one `run` and its output decoding.
pub struct Acquired {
entry: Arc<Loaded>,
}
struct Loaded {
rung: Rung,
session: Mutex<Session>,
last_used: Mutex<Instant>,
}
impl Model {
/// The loaded session, loading it if the reaper took it. Lock it for
/// one run; a scan and a develop click can want the same detector at
/// once, and the second waits on the first.
pub fn acquire(&self) -> Result<Acquired, Error> {
acquire(self.role, self.form, &self.bytes, self.hash)
}
pub fn form(&self) -> Form {
self.form
}
}
impl Acquired {
pub fn lock(&self) -> MutexGuard<'_, Session> {
self.entry.session.lock().unwrap_or_else(|e| e.into_inner())
}
/// Where this session runs.
pub fn rung(&self) -> Rung {
self.entry.rung
}
}
impl Drop for Acquired {
fn drop(&mut self) {
// The clock starts when the use ends, not when it began: a long run
// is not idle time.
*self.entry.last_used.lock().unwrap() = Instant::now();
}
}
type Registry = HashMap<String, Arc<Loaded>>;
static REGISTRY: OnceLock<Mutex<Registry>> = OnceLock::new();
fn registry() -> &'static Mutex<Registry> {
REGISTRY.get_or_init(|| {
std::thread::Builder::new()
.name("inference-reaper".into())
.spawn(|| loop {
std::thread::sleep(Duration::from_secs(5));
release_idle();
})
.expect("spawn inference reaper");
Mutex::new(HashMap::new())
})
}
fn acquire(role: Role, form: Form, bytes: &Arc<[u8]>, hash: u64) -> Result<Acquired, Error> {
api::ensure_installed();
let (rung, cfg) = {
let s = state().lock().unwrap();
let selected = current_rung(&s);
(
effective_rung(&s, selected, role, form, hash),
s.config.clone(),
)
};
let key = format!("{role:?}:{}", engines::key_of(rung, hash));
if let Some(entry) = registry().lock().unwrap().get(&key).cloned() {
*entry.last_used.lock().unwrap() = Instant::now();
return Ok(Acquired { entry });
}
// Built outside the registry lock: a TensorRT or MIGraphX engine load
// is long enough that another role's acquire should not wait on it.
let session = session::build(rung, role, bytes, &cfg)?;
log::debug!("inference: {role:?} loaded on {}", rung.label());
let entry = Arc::new(Loaded {
rung,
session: Mutex::new(session),
last_used: Mutex::new(Instant::now()),
});
let mut reg = registry().lock().unwrap();
// Two acquires raced; keep the first, drop this one.
let entry = reg.entry(key).or_insert_with(|| entry.clone()).clone();
Ok(Acquired { entry })
}
/// Unload every session idle for longer than the decay. The reaper does
/// this every five seconds. A session in use survives until its run ends:
/// the `Acquired` holds it, the registry merely forgets it.
pub fn release_idle() {
let decay = match state().lock().unwrap().config.decay {
Duration::ZERO => DEFAULT_DECAY,
d => d,
};
let now = Instant::now();
registry()
.lock()
.unwrap()
.retain(|_, e| now.duration_since(*e.last_used.lock().unwrap()) < decay);
}
/// Unload every session now, decay or not — what a low-memory signal
/// asks for. Sessions mid-run finish first.
pub fn release_all() {
registry().lock().unwrap().clear();
}
/// Unload every session of `role` now — "I am done segmenting".
pub fn unload(role: Role) {
let prefix = format!("{role:?}:");
registry()
.lock()
.unwrap()
.retain(|k, _| !k.starts_with(&prefix));
}
/// How many sessions are loaded, for the settings row and the tests.
pub fn loaded() -> usize {
registry().lock().unwrap().len()
}
#[derive(Debug, thiserror::Error)]
pub enum Error {
#[error(transparent)]
Inference(#[from] ort::Error),
#[error("reading model: {0}")]
Io(#[from] std::io::Error),
}
/// What the probe writes and the next launch reads (§4 step 3).
#[derive(Clone, Debug, Default, Serialize, Deserialize)]
struct Cache {
/// Runtime, driver, hardware and model identity; any change re-probes.
fingerprint: String,
rung: Option<Rung>,
reason: String,
/// Model hashes whose engine exists on disk, per compiling rung.
compiled: BTreeSet<String>,
/// Rungs that failed under this fingerprint, and why. Not retried until
/// the fingerprint changes: a wedged driver must not cost every launch
/// thirty seconds.
failed: Vec<(Rung, String)>,
/// Engine keys whose compile the process died inside, launch after
/// launch (`probe::attempt`). Left on the fallback until the
/// fingerprint changes. Defaulted, so a cache from before this field
/// still reads.
#[serde(default)]
refused: BTreeSet<String>,
}
struct State {
config: Config,
cache: Cache,
probing: bool,
wanted: usize,
}
static STATE: OnceLock<Mutex<State>> = OnceLock::new();
fn state() -> &'static Mutex<State> {
STATE.get_or_init(|| {
Mutex::new(State {
config: Config::default(),
cache: Cache::default(),
probing: false,
wanted: 0,
})
})
}
/// Choose the runtime and start the probe. Idempotent; the first call wins.
///
/// Returns at once: the probe and any engine compilation run on their own
/// low-priority thread, and every request meanwhile is served by the floor
/// (§4). Never blocks the first frame.
pub fn init(config: Config) {
let runtime = api::install(&config.runtime_dirs);
{
let mut s = state().lock().unwrap();
if s.probing || s.cache.rung.is_some() {
return;
}
s.config = config;
s.probing = true;
}
log::info!("inference: runtime {}", runtime.label());
std::thread::Builder::new()
.name("inference-probe".into())
.spawn(move || {
probe::run(runtime);
engines::run();
})
.expect("spawn inference probe");
}
/// Make sure `ort` has an API table, for code that drives `ort` directly.
/// [`open`] does this itself; only the M1 probe example needs it by name.
pub fn ensure_runtime() {
api::ensure_installed();
}
/// The line for the settings row.
pub fn status() -> Status {
let s = state().lock().unwrap();
let rung = current_rung(&s);
Status {
runtime: api::runtime(),
rung,
reason: s.cache.reason.clone(),
// Only what explains the selection: on an AMD machine the NVIDIA
// rungs "not enabled in this build" say nothing about why MIGraphX
// was taken. With the floor selected, everything tried is above it.
failed: s
.cache
.failed
.iter()
.filter(|(r, _)| *r > rung)
.cloned()
.collect(),
probing: s.probing,
engines: if rung.compiles() {
(s.cache.compiled.len(), s.wanted)
} else {
(0, 0)
},
}
}
fn current_rung(s: &State) -> Rung {
if s.probing {
Rung::Cpu
} else {
s.cache.rung.unwrap_or(Rung::Cpu)
}
}
/// The file to load for `role` under the current selection, and its form.
///
/// A rung that wants int8 gets the `.int8.onnx` sibling of the canonical file
/// if it exists; otherwise the canonical file, on the rung's fallback. A
/// caller adds [`form_suffix`] to the `model_id` it records.
pub fn resolve_model(role: Role, canonical: &Path) -> (PathBuf, Form) {
let rung = current_rung(&state().lock().unwrap());
if rung.serves(role) && rung.form(role) == Form::Int8 {
let sibling = int8_sibling(canonical);
if sibling.is_file() {
return (sibling, Form::Int8);
}
}
(canonical.to_path_buf(), Form::F32)
}
fn int8_sibling(canonical: &Path) -> PathBuf {
let stem = canonical
.file_stem()
.map(|s| s.to_string_lossy().into_owned())
.unwrap_or_default();
canonical.with_file_name(format!("{stem}.int8.onnx"))
}
/// What a form appends to a detector's `model_id` (§7).
pub fn form_suffix(form: Form) -> &'static str {
match form {
Form::F32 => "",
Form::Int8 => "_i8",
}
}
/// A handle on the model `bytes` in `role`.
///
/// Loads it once here, so a graph the runtime rejects fails at
/// construction and not on the first image; what happens to that session
/// afterwards is the registry's business (see [`Model`]).
///
/// Works without [`init`] — a test, or the examples — by installing tract
/// and using the CPU rung, which is exactly what every consumer did before
/// this crate existed.
pub fn open(role: Role, form: Form, bytes: &[u8]) -> Result<Model, Error> {
let bytes: Arc<[u8]> = Arc::from(bytes);
let hash = engines::hash(&bytes);
acquire(role, form, &bytes, hash)?;
Ok(Model {
role,
form,
bytes,
hash,
})
}
/// Where a request lands: the selected rung unless the role's precision rule,
/// the form on offer, or a missing engine says one lower (§6 step 4).
fn effective_rung(s: &State, selected: Rung, role: Role, form: Form, hash: u64) -> Rung {
let mut rung = selected;
if !rung.serves(role) || rung.form(role) != form {
// The embedder on a Hexagon device, or an f32 detector where the int8
// sibling was missing: neither can go to the NPU.
rung = rung.fallback();
}
if rung.compiles() && !s.cache.compiled.contains(&engines::key_of(rung, hash)) {
rung = rung.fallback();
}
rung
}
#[cfg(test)]
mod tests {
use super::*;
/// The registry is one per process, so these run one at a time.
static SERIAL: Mutex<()> = Mutex::new(());
fn serial() -> MutexGuard<'static, ()> {
SERIAL.lock().unwrap_or_else(|e| e.into_inner())
}
/// The smallest shipped graph, if this checkout has the weights; a test
/// suite that needs a research-licensed download is one that does not
/// run in CI (docs/dev/faces.md §3), so absence is a skip.
fn probe_bytes() -> Option<Vec<u8>> {
let path = concat!(
env!("CARGO_MANIFEST_DIR"),
"/../../models/face/scrfd_500m_640.onnx"
);
let bytes = std::fs::read(path).ok()?;
(bytes.len() > 100_000).then_some(bytes)
}
#[test]
fn two_handles_on_one_model_share_one_session() {
let _serial = serial();
let Some(bytes) = probe_bytes() else { return };
release_all();
let a = open(Role::Detector, Form::F32, &bytes).unwrap();
let b = open(Role::Detector, Form::F32, &bytes).unwrap();
assert_eq!(loaded(), 1);
let (x, y) = (a.acquire().unwrap(), b.acquire().unwrap());
assert!(Arc::ptr_eq(&x.entry, &y.entry));
}
#[test]
fn a_released_model_reloads_on_its_next_use() {
let _serial = serial();
let Some(bytes) = probe_bytes() else { return };
release_all();
let model = open(Role::Detector, Form::F32, &bytes).unwrap();
assert_eq!(loaded(), 1);
release_all();
assert_eq!(loaded(), 0);
let acquired = model.acquire().unwrap();
assert_eq!(loaded(), 1);
assert_eq!(acquired.lock().inputs().len(), 1);
}
#[test]
fn an_idle_session_decays_and_a_used_one_does_not() {
let _serial = serial();
let Some(bytes) = probe_bytes() else { return };
release_all();
state().lock().unwrap().config.decay = Duration::from_millis(50);
let model = open(Role::Detector, Form::F32, &bytes).unwrap();
// Used within the decay: stays.
std::thread::sleep(Duration::from_millis(30));
drop(model.acquire().unwrap());
release_idle();
assert_eq!(loaded(), 1);
// Idle past it: goes.
std::thread::sleep(Duration::from_millis(80));
release_idle();
assert_eq!(loaded(), 0);
state().lock().unwrap().config.decay = Duration::ZERO;
}
#[test]
fn unload_by_role_leaves_the_other_roles() {
let _serial = serial();
let Some(bytes) = probe_bytes() else { return };
release_all();
let _d = open(Role::Detector, Form::F32, &bytes).unwrap();
let _s = open(Role::Segmenter, Form::F32, &bytes).unwrap();
assert_eq!(loaded(), 2);
unload(Role::Segmenter);
assert_eq!(loaded(), 1);
}
#[test]
fn the_hexagon_never_takes_the_embedder() {
assert!(!Rung::Hexagon.serves(Role::Embedder));
assert!(!Rung::Hexagon.serves(Role::Denoiser));
assert!(Rung::Hexagon.serves(Role::Detector));
assert_eq!(Rung::Hexagon.form(Role::Detector), Form::Int8);
// A detector offered in f32 on a Hexagon device lands on the CPU.
let s = State {
config: Config::default(),
cache: Cache {
rung: Some(Rung::Hexagon),
..Cache::default()
},
probing: false,
wanted: 0,
};
assert_eq!(
effective_rung(
&s,
Rung::Hexagon,
Role::Embedder,
Form::F32,
engines::hash(b"")
),
Rung::Cpu
);
assert_eq!(
effective_rung(
&s,
Rung::Hexagon,
Role::Detector,
Form::F32,
engines::hash(b"")
),
Rung::Cpu
);
// An int8 detector whose context is not compiled yet: also the CPU.
assert_eq!(
effective_rung(
&s,
Rung::Hexagon,
Role::Detector,
Form::Int8,
engines::hash(b"")
),
Rung::Cpu
);
}
#[test]
fn coreml_takes_a_compiled_detector_and_never_the_embedder() {
let hash = engines::hash(b"detector");
let mut s = State {
config: Config::default(),
cache: Cache {
rung: Some(Rung::CoreMl),
..Cache::default()
},
probing: false,
wanted: 0,
};
let on = |s: &State, role| effective_rung(s, Rung::CoreMl, role, Form::F32, hash);
// Before its program is compiled the detector waits on the CPU.
assert_eq!(on(&s, Role::Detector), Rung::Cpu);
s.cache.compiled.insert(engines::key_of(Rung::CoreMl, hash));
assert_eq!(on(&s, Role::Detector), Rung::CoreMl);
// The embedder does not move, compiled or not (§7).
assert_eq!(on(&s, Role::Embedder), Rung::Cpu);
}
#[test]
fn the_status_reports_only_the_rungs_above_the_selection() {
let _serial = serial();
let failed = vec![
(Rung::TensorRt, "not enabled".to_string()),
(Rung::Cuda, "not enabled".to_string()),
];
let before = state().lock().unwrap().cache.clone();
state().lock().unwrap().cache = Cache {
rung: Some(Rung::MiGraphX),
failed: failed.clone(),
..Cache::default()
};
// An AMD desktop: the NVIDIA rungs below MIGraphX are not the story.
assert!(status().failed.is_empty());
// An NVIDIA desktop on the CUDA provider: TensorRT's failure is.
state().lock().unwrap().cache.rung = Some(Rung::Cuda);
assert_eq!(status().failed, vec![failed[0].clone()]);
// The floor: everything tried explains it.
state().lock().unwrap().cache.rung = Some(Rung::Cpu);
assert_eq!(status().failed.len(), 2);
state().lock().unwrap().cache = before;
}
#[test]
fn the_status_line_reads_as_the_floor_before_init() {
let _serial = serial();
let s = status();
assert_eq!(s.rung, Rung::Cpu);
assert!(s.line().starts_with("CPU"), "{}", s.line());
}
}