Replace SipHash with identity hasher on all hot-path HashMaps keyed by
ActorAddress. Since addresses are crypto-random, the first 8 bytes serve
as an excellent hash directly. Microbenchmarks show 1.9-4.6x lookup
speedup depending on map size.
- Custom Hash impl for ActorAddress (8-byte write_u64 instead of 32)
- AddrHasher/AddrBuildHasher identity hasher in delivery.rs
- AddrMap<V>/AddrSet type aliases used in 7 HashMap sites
- Stop-requests is_empty() short-circuit in tick_all inner loop
- 3 new behavioral tests, component microbenchmarks
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
New benchmark group measuring named spawn/lookup (~2.4µs), group publish
(linear O(N)), monitor setup, and ask roundtrip (~4.5µs). All registry
operations efficient with minimal overhead vs baseline operations.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace blind round-robin placement with load-aware strategy that reads
per-worker stats (actor count + mailbox depth) and biases toward lighter
workers. Falls back to round-robin when stats are equal (initial burst).
Deep research on work stealing across Tokio (steal-half, LIFO slot),
Go (M:N scheduler), BEAM (proactive migration), and ForkJoinPool.
Full actor migration is feasible but deferred due to message-loss window.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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>
Adds some basic benchmarking, stress tests. They still need to be properly examined to ensure they are testing the correct properties, but fit for "good enough". Implements the HybridChannel type, which features a channel buffer that can withstand overflows. It does so by providing a dequeue behind a mutex. Without overflow, will push messages into the lock free ArrayQueue implemented by crossbeam_queue; when that buffer fills, will use the locking portion provided by the Mutex<VecDequeue>.
In the future we can even further optimize this, perhaps with some linked list implementations of lock-free channels, but, like the benchmarks, this fits the "good enough" bar for now.
