shoney.arickathil
d24c705860
- Float full stack: literals (fraction/exponent; `0..10` still a range), f64
opcodes 34-41, @table column, WAL bit-exact replay, json fractions in and
shortest-round-trip out. IEEE-quiet — FDIV never traps where DIV does.
- Bytes: a wo_str with its own class id, so alloc/free/copy are shared but no
Text builtin accepts one; len/at/slice/eq/concat, base64 both ways, json
boundary as base64; TEXT_COPY preserves the kind.
- No implicit Int/Float mixing (WO-E201 in the typechecker, not the emitter,
which picks the opcode from one side and would misread the other).
- One IEEE deviation: float_cmp total order (NaN last, -0.0 == +0.0) for
indexes and order-by, keys canonicalized to match. `?Float` nil is a
reserved quiet NaN — the zero word is +0.0, WO_NIL_SCALAR's bits are -2.0.
- Renderer prefers fixed over exponential in 1e-6..1e21: pure shortest makes
a price of 900.0 read `9e+02`. One renderer for interp/json/float_to_text.
- Fixed en route: lexer double-counted the leading digit; is_scalar_shaped
took Float/Bytes as Int-shaped; Bytes ownership needed a shared heap-scalar
predicate or temps never dropped; order-by bit-compared negatives backwards.
- Iteration 17: `kind = "library"` (absent = program; bad value = WO-E109),
entry-less check mode retiring the `--emit` workaround, Go's `internal/` as
WO-E108 at the consumer's `use`. Driver-only; VM/.wob/GC untouched.
- Framework reorg: internal/{parse,serve}.wo; http/form.wo split out to keep
media_type/form_values public (parse.wo had grown public surface).
- Docs: link audit (97 -> 88 broken, conflict markers resolved, 2 duplicate
stories removed), 00-code-review verified 26/27, iterations re-sequenced.
- Also carries the pre-staged pub(read)/using/#if work from the index.
- Gates: corpus 103/0, test_wal 156/0, web-app 26/0, oop-accept ALL MET.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
104 lines
5.3 KiB
Markdown
104 lines
5.3 KiB
Markdown
# Iteration 11 — fibers (the 8+11 concurrency arc, part 2)
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> Format: `product/story-iteration-template`. Part of
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> [Story — one language, one runtime, one database, one binary](../00-story.md).
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>
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> **REFINED 2026-08-20** (developer decisions, no code): 8 and 11 ship as
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> **one arc** — the DB becomes an actor on an owner shard
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> ([iteration 8](08-shard-actor-runtime.md)'s decision), so serving
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> shards must PARK on cross-shard replies, which is this iteration.
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> The spawn-surface question below is SETTLED: one unified actor-address
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> surface (`spawn` returns an address, fiber or remote alike; `send`
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> moves ownership; same-heap sends take the cheap path). The arc's
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> driving workload is [iteration 24: chat](24-chat-websocket-workload.md)
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> — fiber-per-WebSocket-connection is the serving model that retires the
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> framework's close-when-idle keep-alive policy.
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>
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> **STAGE-1 SUBSTANCE LANDED 2026-08-20** (branch `concurrency-arc`):
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> reduction-budget fibers (back-edge accounting — the livelock lesson is
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> in the plan's deviations), `spawn`/`send`/`actor M`, one-message-at-a-
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> time delivery, main-return reap, fiber-trap isolation, and parked
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> `net`/`time` builtins on the io_uring-first per-shard I/O plane
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> (`WO_IO=uring|epoll`, epoll fallback proven). Demonstrated by
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> `docs/examples/fibers` (`just fibers` 8/0). The shard-context criteria
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> (TID assertions, cross-shard sends, blue-green drain reuse) close with
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> the arc's stage 2.
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## Goals
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- Concurrency **inside** a shard the doctrine way: cooperative fibers
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scheduled by the VM — a fiber is the interpreter state wovm already
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isolates (register windows + frame stack + pc), made per-fiber. One
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kernel task per core stays the rule; thousands of fibers run above it
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where the kernel tops out at hundreds of threads (CFS O(log N),
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~8 MiB + ~20 µs per thread vs an arena-allocated fiber context).
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- **Preemption by reduction budget**, the Erlang shape: the dispatch loop
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counts down and parks the fiber at zero — no signals, no safepoints, no
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stack copying, deterministic replay.
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- **Blocking builtins park instead of block** on server shards: the same
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`net`/`time`/`fs` calls that block the thread in program mode hand their
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fd to the shard's epoll/io_uring loop and resume on completion. One API,
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same source text, no async/await, no function coloring — ever.
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- Cross-fiber sends follow the iteration 8 rule — ownership moves — on the
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cheaper same-heap path.
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## Acceptance Criteria
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- What to achieve?
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- **Given** a shard running thousands of spawned fibers with one hot
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compute loop among them,
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- **when** the reduction budget expires,
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- **then** the hot fiber parks, every other fiber makes progress
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(starvation-free corpus fixture), and output is identical across
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runs (deterministic scheduling).
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- What to achieve?
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- **Given** a fiber blocked in a stdlib builtin on a server shard,
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- **when** the completion arrives on the shard's event loop,
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- **then** the fiber resumes with the result while the shard served
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other fibers in the interim — one OS thread, verified by TID.
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- What to achieve?
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- **Given** a parked fiber at shard shutdown,
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- **when** the shard unwinds it,
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- **then** every drop map runs (ASan zero leaks) — parked fibers die
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as cleanly as trapped ones. (Iteration 26's blue-green drain reuses
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exactly this unwind path.)
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- What to achieve?
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- **Given** TRACED objects (GC-ness inferred since 7b) referenced only
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from a parked fiber's frames,
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- **when** the per-shard mark-sweep collector scans,
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- **then** parked fibers' frames are roots exactly as the live frame
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stack is (`vm_gc_roots` grows fiber awareness) — nothing live is
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collected, nothing dead survives. (Originally said `@gc`; restated
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2026-08-20 in inference terms.)
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## Out Of Scope
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- Fiber migration across shards (ownership doctrine forbids it; cross-shard
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is a message send, iteration 8).
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- Priorities, timers, structured-concurrency policy — recipe-box
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capabilities for a later `.wo` library, not runtime policy.
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- Program mode: stays single-fiber in v1 (blocking legal, log-watcher
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needs nothing more).
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- async/await keyword — permanently rejected surface, not deferred.
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## Info
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- Research note: [`docs/plan/exploration/fibers/00-fibers.md`](../../../plan/exploration/fibers/00-fibers.md)
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— kernel's-eye evidence (task_struct costs, CFS collapse at high task
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counts) and the precedent survey (BEAM reductions adopted; Go stack
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copying and Tokio coloring rejected; Loom's park-under-blocking-API
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matches the stdlib posture).
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- Vision origin: [blue-green vision §3](../../../plan/exploration/blue-green-vm/00-vision.md);
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iteration 8's scheduler is the substrate this extends.
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- Open questions to settle in the spec — REDUCED 2026-08-20: the spawn
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surface is settled (the unified actor address, iteration 8 decision 2).
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Still open for the arc's spec: budget size and check granularity,
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parked-fiber drop semantics, run-queue fairness (FIFO v1), and how a
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parked fiber's borrow state interacts with the shard's GC safepoints.
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## Proposed Solution
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- No implementation plan exists yet — this iteration starts with the
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brainstorming → spec → writing-plans chain (the superpowers path every
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prior iteration followed), then executes that plan. The research note
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above is the brainstorm's entry material.
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