Every ISerializable carried SerializedThread/SerializedPosition/SerializedLength
so WriteSnapshot could gather each entity's bytes from the worker heaps in
dictionary order. The idx records absolute positions, so bin order is free -
the snapshot can be written in worker-heap order instead, and the join inverts:
- Chunks are persistence-homogeneous: SerializeAll declares the owner at each
boundary, publishing the partial chunk on change.
- Workers log segments (owner, slot range, heap start) plus one length per
record as they serialize. Positions are implicit because a worker's writes
are contiguous; identity comes from re-walking the same snapshot slots in
the same order (guaranteed stable - mutations divert to the pending queues
until PostWorldSave), or from an entities log on the fallback path.
- WriteSnapshot routes segments by owner, emits idx entries during the
re-walk, and writes each segment's heap bytes as a single span instead of
one copy per entity, which also speeds up the background write phase.
- Persistence self-payloads keep placement as three private fields on the
~dozens of persistence instances; PushSingle is now typed accordingly.
Net effect: 9 bytes (plus padding) of resident state removed from every item,
mobile, guild, and account on every shard; three interface-property stores
per entity leave the drain hot path (stamping dirtied one cache line per
entity mid-freeze - the lengths log is a single sequential stream); and the
vestigial loader-side length stamp is gone. The transient cost is ~4 bytes
per entity in pooled per-worker logs that are released after each write.
The save format is unchanged (idx v3, same loader); only the write-side
mechanics moved. Adds an end-to-end round-trip test that drives real workers
through the chunk source, snapshots from the segment logs, and reloads.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Removes the per-entity handoff from the freeze entirely. GenericEntityPersistence
publishes 4096-slot ranges over its dictionary's backing entries array, and workers
serialize occupied slots (value != null) directly via a ShadowEntry<TValue> struct
that mirrors the runtime's private Dictionary Entry layout. Safe because the
dictionary is frozen during Saving (mutations divert to the pending safety queues).
The layout is proven at startup before any code reads through it: validation
measures the true Entry stride via precise allocation accounting (so all shadow
reads are guaranteed in-bounds), then compares every key and value of a churned,
resized, freelist-exercised dictionary reading value slots as raw pointer bits
only - never materializing a managed reference until the layout is proven. If a
future runtime changes Dictionary internals, validation fails and saves fall back
to the enumerate-and-push path with a logged warning.
The main thread now joins the drain through an inline (threadless) worker after
publishing work, instead of idling while the thread workers finish - worth a full
worker share on the freeze and proportionally more on low-core hosts.
Measured through the real pipeline classes (24 cores, 10M entities, 1.7GB, dense
2-byte write profile): publish cost drops from ~55ms to ~0.1ms, the freeze is now
bound by pure serialize throughput at ~99ms steady state (vs ~740ms before this
branch, ~7.5x), and the first save after boot drops from ~468ms to ~139ms because
fine-grained ranges self-balance without needing size estimates.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
