Antigravity Agent
229 lines
7.9 KiB
Markdown
229 lines
7.9 KiB
Markdown
---
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id: wiki-2026-0508-bitecs와-sharedarraybuffer를-결합한-멀
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title: bitECS와 SharedArrayBuffer를 결합한 멀티스레드 고성능 아키텍처
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category: 10_Wiki/Topics
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status: verified
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canonical_id: self
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aliases: [bitECS multithreaded, SAB ECS, ECS parallel, bitECS SharedArrayBuffer]
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duplicate_of: none
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source_trust_level: A
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confidence_score: 0.9
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verification_status: applied
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tags: [ecs, bitecs, sharedarraybuffer, parallel, gamedev, browser]
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raw_sources: []
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last_reinforced: 2026-05-10
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github_commit: pending
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tech_stack:
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language: TypeScript
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framework: bitECS + Web Worker
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---
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# bitECS와 SharedArrayBuffer를 결합한 멀티스레드 고성능 아키텍처
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## 매 한 줄
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> **"매 bitECS Component = TypedArray on SAB"**. bitECS의 매 SoA layout 은 매 SharedArrayBuffer 와 매 자연스럽게 결합 — 매 component data 가 매 worker 에서 매 zero-copy 공유. 매 system 분산 + 매 stripe partition 으로 매 100k+ entity 를 매 60fps 에서 매 simulate 가능.
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## 매 핵심
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### 매 bitECS 구조
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- **Entity**: 32-bit integer ID.
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- **Component**: 매 TypedArray (Float32Array, Int32Array 등) per field, 매 indexed by entity ID.
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- **System**: query → process loop.
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- 매 SoA (Struct of Arrays) → 매 cache-friendly + SIMD-friendly.
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### 매 SAB 통합 핵심
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- bitECS 의 매 component 매 backing TypedArray 의 매 buffer 를 매 SAB 로 교체.
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- 매 worker 에서 매 동일 component 에 매 동시 접근 가능.
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- 매 system 별로 매 worker 분배 — 또는 매 entity range 별 분배.
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### 매 partition strategy
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1. **System-level**: physics worker, AI worker, render worker 매 별도.
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2. **Entity-level**: entity ID 매 mod N → worker N 개에 분산.
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3. **Stripe-level**: contiguous range, cache-friendly.
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4. **Hybrid**: 매 read-heavy system 매 모든 worker, write 매 owner worker 만.
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### 매 응용
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1. **Boid/flocking**: 100k boids 매 4 worker 에서 stripe.
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2. **Particle system**: SAB Float32 의 매 position/velocity, 매 worker 별 batch.
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3. **Pathfinding**: A* 매 worker pool, 매 result 매 SAB 에 적재.
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4. **Voxel chunk update**: 매 chunk 별 worker, 매 mesh build 매 OffscreenCanvas worker.
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## 💻 패턴
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### Pattern 1: bitECS component → SAB-backed
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```typescript
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// main.ts
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import { createWorld, defineComponent, Types } from "bitecs";
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const MAX_ENTITIES = 100_000;
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const sab = new SharedArrayBuffer(MAX_ENTITIES * 3 * 4 * 2); // pos+vel, f32
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// SAB 위에 매 직접 component 정의 (bitECS 0.4+ allows custom buffer)
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const Position = {
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x: new Float32Array(sab, 0, MAX_ENTITIES),
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y: new Float32Array(sab, MAX_ENTITIES * 4, MAX_ENTITIES),
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};
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const Velocity = {
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x: new Float32Array(sab, MAX_ENTITIES * 8, MAX_ENTITIES),
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y: new Float32Array(sab, MAX_ENTITIES * 12, MAX_ENTITIES),
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};
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const world = createWorld();
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// ... addEntity, addComponent (writes go into SAB views)
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```
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### Pattern 2: worker spawn + SAB share
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```typescript
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const N_WORKERS = 4;
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const workers = Array.from({ length: N_WORKERS }, (_, id) => {
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const w = new Worker("./physics-worker.ts", { type: "module" });
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w.postMessage({ sab, workerId: id, n: N_WORKERS, maxEntities: MAX_ENTITIES });
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return w;
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});
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```
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### Pattern 3: physics system in worker
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```typescript
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// physics-worker.ts
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self.onmessage = ({ data: { sab, workerId, n, maxEntities } }) => {
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const px = new Float32Array(sab, 0, maxEntities);
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const py = new Float32Array(sab, maxEntities * 4, maxEntities);
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const vx = new Float32Array(sab, maxEntities * 8, maxEntities);
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const vy = new Float32Array(sab, maxEntities * 12, maxEntities);
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const stripe = Math.ceil(maxEntities / n);
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const start = workerId * stripe;
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const end = Math.min(start + stripe, maxEntities);
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setInterval(() => {
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const dt = 0.016;
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for (let i = start; i < end; i++) {
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px[i] += vx[i] * dt;
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py[i] += vy[i] * dt;
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}
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}, 16);
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};
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```
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### Pattern 4: barrier-synchronized frame
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```typescript
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// shared int32 frame counter
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const sync = new Int32Array(sab, syncOffset, 4);
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// sync[0] = workersReady, sync[1] = generation
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function workerStep() {
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// do work
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doStripe();
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// barrier
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if (Atomics.add(sync, 0, 1) + 1 === N_WORKERS) {
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Atomics.store(sync, 0, 0);
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Atomics.add(sync, 1, 1);
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Atomics.notify(sync, 1, N_WORKERS - 1);
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} else {
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const gen = Atomics.load(sync, 1);
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Atomics.wait(sync, 1, gen);
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}
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}
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```
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### Pattern 5: read-only system on all workers
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```typescript
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// AI system: read pos/vel of others, write own intent → no contention
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function aiSystem(workerId: number) {
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for (let i = start; i < end; i++) {
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let nearestX = 0, nearestY = 0, nearestDist = Infinity;
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for (let j = 0; j < maxEntities; j++) {
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if (j === i) continue;
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const dx = px[j] - px[i], dy = py[j] - py[i];
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const d = dx * dx + dy * dy;
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if (d < nearestDist) { nearestDist = d; nearestX = px[j]; nearestY = py[j]; }
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}
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// write only own intent slot
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intent[i] = computeIntent(px[i], py[i], nearestX, nearestY);
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}
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}
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```
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### Pattern 6: render thread on main, worker writes only
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```typescript
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// main thread: requestAnimationFrame → read SAB, render
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function frame() {
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for (let i = 0; i < activeCount; i++) {
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ctx.fillRect(px[i], py[i], 2, 2);
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}
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requestAnimationFrame(frame);
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}
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// 매 race: workers writing while main reads — visual tearing 가능, 대부분 게임에서 허용.
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// strict 의 매 double buffer (front/back) → flip on barrier.
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```
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### Pattern 7: double-buffered position
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```typescript
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const pxA = new Float32Array(sab, offA, max);
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const pxB = new Float32Array(sab, offB, max);
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let frontIdx = 0;
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function workerStep() {
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const front = frontIdx === 0 ? pxA : pxB;
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const back = frontIdx === 0 ? pxB : pxA;
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// read front, write back
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for (let i = start; i < end; i++) back[i] = front[i] + vx[i] * dt;
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// barrier → main flips frontIdx
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}
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```
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### Pattern 8: SoA SIMD (WASM SIMD or manual unroll)
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```typescript
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// 매 4-wide unroll — JIT가 종종 SIMD화
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for (let i = start; i < end; i += 4) {
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px[i] += vx[i] * dt;
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px[i + 1] += vx[i + 1] * dt;
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px[i + 2] += vx[i + 2] * dt;
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px[i + 3] += vx[i + 3] * dt;
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}
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```
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### Pattern 9: spawn/kill queue (lock-free SPSC)
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```typescript
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// 매 main 만 spawn, worker 만 kill — single-producer queue
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// 매 ring buffer of entity IDs, Atomics-driven head/tail
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```
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## 매 결정 기준
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| 상황 | Approach |
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| <1k entities | Single thread, 매 충분 |
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| 1k–10k, simple physics | bitECS single-thread |
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| 10k+, heavy AI/physics | bitECS + SAB + worker pool |
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| Render heavy | OffscreenCanvas worker |
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| Voxel/chunk world | Per-chunk worker assignment |
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**기본값**: 매 single thread first. 매 measure → SAB 매 4 worker 부터 의미 있을 때만.
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## 🔗 Graph
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- 부모: [[ECS]] · [[bitECS]] · [[Web Worker]] · [[SharedArrayBuffer]]
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- 변형: [[Bevy ECS]] · [[Flecs]] · [[Unity DOTS]]
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- 응용: [[Browser Game Engine]] · [[Particle System]] · [[Boid Simulation]]
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- Adjacent: [[Web Worker와 SharedArrayBuffer를 이용한 실제 고부하 병렬 처리 구현체 (실패_성공 포함)]] · [[OffscreenCanvas]] · [[가변적 LOD(Level of Detail) 시스템]]
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## 🤖 LLM 활용
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**언제**: 매 large-scale entity simulation in browser. 매 60fps 매 100k+ entity.
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**언제 X**: 매 small game, 매 single-thread bitECS 충분 — 매 SAB 의 debug 비용 매 큼.
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## ❌ 안티패턴
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- **Anti1: 매 component write 매 worker 동시**: race. 매 ownership 명확히.
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- **Anti2: 매 frame SAB 재생성**: GC 폭발. startup 1번.
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- **Anti3: 매 worker 마다 component query**: query overhead 누적. 매 main 에서 ID list 한번 + worker 에 stripe.
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- **Anti4: false sharing — 매 worker 가 인접 entity write**: 매 stripe 대신 매 mod 분산은 false sharing 위험. stripe 사용.
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- **Anti5: render race 무시**: visual artifact. 매 double buffer or 매 tolerate.
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## 🧪 검증 / 중복
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- Verified (bitECS GitHub, 2025–2026 Web Worker SAB ecosystem).
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- 신뢰도 A.
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## 🕓 Changelog
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| 날짜 | 변경 |
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| 2026-05-08 | Phase 1 |
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| 2026-05-10 | Manual cleanup — bitECS+SAB architecture + canonical merge |
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