shoney.arickathil
2a4c304378
- done/ (11): 1, 2, 3, 4, 6, 7, 7b, 9, 9b, 15, 16 — landed iterations (9/9b remainders live in the post-12 drain list, not in the files) - refine/ (8): 9c, 9d, 9e, 9f, 9g, 11, 13, 14 — everything marked "no spec yet / brainstorm before planning" - root keeps: 00-story (index), 05 (partial, plan 8 open), 8/10/12 (specs or plans exist), 17 (parked, spec+plan approved), 18 (next) - every cross-reference re-pathed and VERIFIED resolving: board, specs, plans, employee-list README, story table, intra-story links (moved files' relative links deepened one level; done/7b's 9e pointer now crosses to refine/) - pre-existing dead link noted, not touched: refine/11-fibers.md points at docs/plan/exploration/fibers/00-fibers.md which does not exist (predates the move) Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
58 lines
2.4 KiB
Markdown
58 lines
2.4 KiB
Markdown
# Iteration 8 — shard-actor runtime
|
||
|
||
> Format: `product/story-iteration-template`. Part of
|
||
> [Story — one language, one runtime, one database, one binary](00-story.md).
|
||
|
||
## Goals
|
||
|
||
- The runtime scales past one core the doctrine way: pinned thread-per-core
|
||
shards, each owning its own heap and event loop; cross-shard
|
||
communication is a message send that **moves ownership** — shared mutable
|
||
state never exists.
|
||
- The language grows `spawn` and message send; garbage collection stays
|
||
per-shard, so no global pause appears at any core count.
|
||
|
||
## Acceptance Criteria
|
||
|
||
- What to achieve?
|
||
- **Given** a program spawning actors across shards,
|
||
- **when** an owned object is sent to another shard,
|
||
- **then** the sender can no longer touch it (compile-time move), the
|
||
receiver owns it, and its eventual free routes back to its
|
||
allocation-home arena.
|
||
- What to achieve?
|
||
- **Given** debug builds with shard-ownership asserts,
|
||
- **when** the deterministic actor corpus runs under ASan and TSan,
|
||
- **then** zero races, zero leaks, and identical output across runs.
|
||
- What to achieve?
|
||
- **Given** a `@gc` reference,
|
||
- **when** code attempts to send it cross-shard,
|
||
- **then** the compiler rejects it — aliased references cannot cross
|
||
heap boundaries.
|
||
|
||
## Out Of Scope
|
||
|
||
- Fibers/green threads (recorded in the blue-green vision §3; extends this
|
||
scheduler later).
|
||
- Cross-shard transactions (the database iteration's 2PC concern, later).
|
||
|
||
## Info
|
||
|
||
- The C reference (`runtime/wo-rt.c`, phases A–F) is the substrate: epoll
|
||
loops, eventfd mail, the machinery this iteration lifts into `wovm`.
|
||
- The VM's object header has carried a shard id since iteration 2 — no
|
||
relayout.
|
||
- **Gated by the benchmark (2026-08-15):** this is the "optimize
|
||
multithreading" lever of the performance arc — thread-per-core is a
|
||
throughput/scale claim, so landing it means re-running iteration
|
||
[9e](refine/09e-durability-throughput-scale.md) at the connection/concurrency
|
||
scale it unlocks and recording the before/after delta. It is also where
|
||
the io_uring write path ([9f](refine/09f-io-uring-commit.md)) gets a thread to
|
||
overlap durability against.
|
||
|
||
## Proposed Solution
|
||
|
||
- Execute the existing plan: `docs/superpowers/plans/2026-08-01-shard-actor-vm-runtime.md`
|
||
(pinned-worker scheduler, shard-stamped heaps, MPSC mailbox rings + mail
|
||
eventfds, send-as-move with home-routed frees, gc pacing per tick,
|
||
spawn/send surface, actor corpus).
|