The flip: within each K-instrument chunk (the structural residency bound
from the previous commit), all cells run concurrently on rayon's process-
global pool — the same pool the engine's member/window fan-out already
shares, so cells x members x windows feed one work-stealing scheduler and
the per-cell serial seams (ingest transpose, single-threaded bootstrap)
overlap with other cells' work. Results land in index-addressed slots and
the ordered outputs are rebuilt in document order: byte-identical outcomes
across worker counts and bounds (C1).
Fault routing, restructured for a loop that cannot mid-iterate abort:
member/window faults stay #272-contained inside run_cell; non-containable
faults (incl. registry writes — infrastructure, not cell pathology) latch
an atomic abort flag so unstarted cells never run, and after the join the
lowest document-order fault among completed cells propagates as the run's
error. Nothing partial is persisted at run level on the fatal path.
Property pins: determinism across thread counts and bounds (1-thread/K=1
== 8-thread/K=2), distinct live instruments never exceed K (refcounting
stub runner, 8-thread pool), a dead family store is run-fatal with no
partial campaign-run record, member faults stay contained under the
parallel loop. E2E fixtures (previous commit) pin the CLI prose and
document-order persistence across K.
Verified: workspace suite green, clippy -D warnings clean. rayon enters
aura-campaign under the amended C16 per-case policy (comment in
Cargo.toml, mirroring aura-engine).
closes#277
claude
cf94377f30