COMPLETENGINE — Concurrent Event Simulation Engine

A deterministic, replay-capable engine for modeling thousands of concurrent actors, message queues, and event pools. Designed for engineers who build distributed systems and need to observe every race condition.

ACTORS

concurrent

THROUGHPUT

events / s

LATENCY p99

microseconds

REPLAY

DETERMINISTIC

bit-exact

01 // ENGINE SIGNATURE

// initialize simulation
let engine = Completengine({
  actors: 8192,
  replay: "deterministic",
  seed: 0x5A1CEB0C,
});
engine.run();

02 // CORE PRIMITIVES

◆ Actor — isolated execution unit
◆ Event — immutable message envelope
◆ Queue — ordered priority channel
◆ Scheduler — deterministic dispatcher
◆ Resolver — conflict arbiter

03 // ACTIVE PARAMETERS

tick_rate: 1024 Hz
quantum: 976 μs
heap: 512 MiB
workers: 16 threads
isolation: strict
backpressure: adaptive

[ MODULE 01 ] — PIPELINE TOPOLOGY

§01 ENGINE ARCHITECTURE

NODE:01

EVENT QUEUE

ingress / ordered

IN OUT

NODE:02

SCHEDULER

deterministic dispatch

IN OUT

NODE:03

ACTOR POOL

8192 × isolated

IN OUT

NODE:04

STATE STORE

copy-on-write

IN OUT

NODE:05

CONFLICT RESOLVER

arbitration + replay

IN OUT

NODE:06

REPLAY BUFFER

bit-exact journal

IN OUT

NODE:07

EGRESS / OBSERVER SINK

structured telemetry stream

IN OUT

04 // DATAFLOW INVARIANTS

Every event is stamped with a logical tick and a monotonically increasing sequence id. Re-running an engine with the same seed yields byte-identical state after N ticks.

05 // CONFLICT POLICY

// last-writer-wins with
// deterministic tiebreak
fn resolve(a, b) {
  if a.tick > b.tick { a }
  else if a.tick < b.tick { b }
  else { min_by_seq(a, b) }
}

06 // OBSERVABILITY

▸ per-actor inbox depth
▸ per-queue backpressure ratio
▸ resolver conflict counter
▸ scheduler starvation alerts
▸ replay divergence detector

[ MODULE 02 ] — TEMPORAL TRACE

§02 EVENT TIMELINE

A single tick of the simulation, expanded. Each hex node is an event type that participates in the scheduler’s deterministic ordering. Connections show causal precedence, not wall-clock latency.

SPAWN

t = 0 μs

ENQUEUE

t = 48 μs

DISPATCH

t = 112 μs

CONFLICT

t = 144 μs

RESOLVE

t = 176 μs

COMMIT

t = 208 μs

✓

JOURNAL

t = 240 μs

EMIT

t = 288 μs

[ MODULE 03 ] — SUBSYSTEMS

§03 DEEP DIVE

SUBSYSTEM / A

THE ACTOR MODEL

Each actor is a closed state machine with a private inbox. The engine guarantees that within a tick, an actor processes messages in the exact order they were enqueued, using the actor’s own identifier as a tiebreak across concurrent senders.

Actors never share memory. All communication is an immutable Event envelope routed through the scheduler. This is the load-bearing constraint that makes deterministic replay possible at 8192-way concurrency.

8192actors

64inbox depth

0shared bytes

actor — isolated execution unit

queue — hexagonal prism channel

SUBSYSTEM / B

MESSAGE QUEUES

Queues are ordered, bounded, priority-aware channels. Each queue is modeled as a hexagonal prism: six ingress faces admit messages from different actor shards, and the two caps expose high- and low-priority egress to the scheduler.

Backpressure is adaptive: when a queue fills beyond 85%, the engine propagates a pressure gradient upstream, slowing emitters rather than dropping events. This preserves causal ordering under load.

256queues

85%pressure edge

FIFOper-priority

SUBSYSTEM / C

DETERMINISTIC REPLAY

The replay buffer is an append-only journal of every event’s (tick, seq, source, target, payload_hash). Replaying a journal against a snapshot yields bit-identical state, which makes post-mortem debugging of race conditions trivial: reproduce, inspect, rewind.

Divergence between a live run and its replay triggers an automatic bisect against the journal, narrowing the offending tick in O(log n) steps. This is the engine’s core debugging superpower.

100%determinism

O(log n)bisect

∞rewind depth

event pool — icosahedral shell

[ MODULE 04 ] — INTERFACE

§04 ENGINE INTERFACE

engine.spawn(actor)

engine.send(to, event)

Enqueue an immutable event envelope targeted at an actor. Serialized by the deterministic scheduler.

engine.tick(n)

Advance the simulation by n logical ticks. Blocks until all actors quiesce or backpressure stabilizes.

engine.snapshot()

Serialize engine state into a portable, replay-compatible checkpoint. Typical size: 12–64 MiB.

engine.replay(journal)

Re-run a recorded journal deterministically. Any divergence is reported with tick, actor, and causal chain.

engine.observe(sink)

Attach an observer that receives structured telemetry: per-actor metrics, queue depths, conflict counts.