- spawn placement: round-robin across shards (same-shard when the
engine is absent/single); the actor's mailbox and delivery belong to
its HOME thread — a spawn to another shard travels as an ADOPT
envelope, a send as a SEND envelope (mutex-guarded inbox + eventfd
wake; the spec's lock-free rings stay a disclosed deviation until
9e measures the mutex)
- workers: first envelope triggers lazy full-vm init UNDER the inbox
mutex (TSan caught the memset racing a concurrent push, twice — the
second was inbox_push reading wake_efd outside the lock; both fixed,
gate x8 + battery clean); serve loop = adopt -> run to drained ->
wait on the plane (the wake eventfd is watched by io_uring POLL_ADD
oneshot / epoll level-triggered on BOTH backends)
- ownership across heaps: every allocation stamps rt->shard_id into
the header (the field reserved since iteration 2); a drop on the
wrong shard routes home as a FREE envelope — the owner's arena stays
single-threaded by construction; at teardown routed frees become
no-ops (arenas die wholesale) which is what un-danced the freed-mutex
ASan SEGV the first ordering had
- WO-E222: an actor's state or message type that is (or transitively
contains) an inferred-traced class refuses at the spawn/send — with
round-robin every actor is potentially remote; corpus-pinned
(compile-fail/traced-send, inference-aware: Box contains ?Node)
- determinism narrowed per spec: oop-e2e pins WO_SHARDS=1 (exact
outputs); the fibers gate grows multi-shard SET assertions + a TSan
run (wovm-tsan target; setarch -R fallback for kernel 6.5+ ASLR)
- NEXT_RUNNABLE honors engine shutdown for parked workers (deadlock
hole closed); io_wait's adopt-wake (rc 1) no longer reads as fatal
- battery: oop-e2e 93/0, fibers 10/0 x8 (+WO_IO=epoll), log-watcher
7/0, employee 8/0, web-app 21/0, deps 8/0, runtime tests 16/16
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
- docs/examples/fibers: part 1 is TIMING-FREE and byte-exact — main
sends three messages then burns reductions; each budget expiry hands
the Counter actor exactly one delivery (cooperative mechanics,
preemptive fairness, BEAM's shape); part 2 parks a Sleeper actor
mid-receive on the I/O plane while main keeps ticking — the wake
lands between ticks, proving a sleeping fiber blocks nobody
- the missing "sleeper: up" on the first run was main-return-reap
working as specced (main ended before the deadline); the demo's
window widened so the wake is observable
- scripts/fibers-accept.sh + `just fibers` (8 checks): build, part-1
exact + part-2 ordering invariants on auto/uring/epoll backends,
and an ASan-runtime rebuild+run
- README points at the doctrine writeup (exploration/fibers)
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
