ef87f7e1b9
Research across ractor, tokio, Erlang/OTP BEAM, Linux CFS, and libuv revealed that tick_all drained the entire mailbox per actor per tick, allowing one hot actor to starve all others on the same worker. - Add `actor_message_budget` to RuntimeConfig (default: 64 msgs/actor/tick) - Modify tick_all to break after budget messages, yielding to next actor - budget=0 restores unlimited (backward compatible) behavior - 3 new fairness tests validating hot-cold actor scenarios - New fairness benchmark group (cold_latency_under_pressure, throughput_by_budget) - Fix RuntimeConfig struct literals across workspace crates Inspired by BEAM's 4000-reduction budget and tokio's 128-op cooperative budget. All 45 tests pass (42 original + 3 new). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
30 lines
1.4 KiB
Markdown
30 lines
1.4 KiB
Markdown
# Task Constraints (from user)
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## Scope of Study
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- **Broad survey**: Not just Rust actor frameworks — include:
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- Rust: ractor, actix, kameo, coerce, stakker, xactor, bastion
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- Non-actor runtimes: tokio, C++ node/libuv event loop
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- OS-level: `process` scheduling/logic in operating systems
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- Classic actor systems: Erlang/OTP, Akka/Pekko (JVM)
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- Any widely-used, well-reputed system
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## Priority & Approach
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- **Interleaved**: Pick a topic → analyze competitors → benchmark swactor → improve → repeat
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- **Also improve testing methodology and coverage** based on analysis
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- **Look at bug report histories** of competitor projects for insights
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- Behavioral tests only (Given/When/Then), no white-box/structural tests
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## Code Structure Rules
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- **src/ is frozen**: No new files, no new modules, no structural changes. Only modify existing files in-place.
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- **No new dependencies** on the root crate (swactor's Cargo.toml)
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- May add new crates to `crates/` but they must NOT be pulled into `src/`
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- Cap at ~5 new crates — if approaching that, prune back
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- Integration tests in `tests/`, benchmarks in `benches/`
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- Benchmark execution capped at 2 minutes max
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- All notes go in `CLAUDE/notes/`
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- Report architecture changes in `docs/`
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## Commit Rules
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- All `cargo test` must pass (including feature-gated)
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- Never skip/delete tests for active code
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- If a fix takes >3 attempts, log and move on
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