chore(brain): ASTRA 성장 자산 동기화 — 기능 인벤토리·growth(약점프로필/학습큐)·일화기억·장기기억·회의록 원문

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+---
+id: wiki-2026-0508-orinoco
+title: Orinoco (V8 GC project)
+category: 10_Wiki/Topics
+status: verified
+canonical_id: self
+aliases: [V8 Orinoco, Orinoco GC, Concurrent V8 GC]
+duplicate_of: none
+source_trust_level: A
+confidence_score: 0.9
+verification_status: applied
+tags: [v8, gc, performance, concurrent-marking, runtime]
+raw_sources: []
+last_reinforced: 2026-05-10
+github_commit: pending
+tech_stack:
+  language: cpp
+  framework: v8
+---
+
+# Orinoco
+
+## 매 한 줄
+> **"매 V8의 GC를 stop-the-world에서 incremental · concurrent · parallel multi-threaded GC로 전환한 multi-year 프로젝트."**. 2016년 시작, 2017-2019 Concurrent Marking · Parallel Scavenger · Lazy Sweeping 차례 도입. 2026 현재 V8 13.x base GC architecture가 Orinoco — pause time을 100ms+ → <1ms로 감소.
+
+## 매 핵심
+
+### 매 핵심 기법
+- **Parallel Scavenger** (Young Gen): 매 multiple worker가 semi-space copy 병렬화.
+- **Concurrent Marking** (Old Gen): 매 worker thread가 mutator와 병행 mark — main thread는 거의 미 pause.
+- **Incremental Marking**: 매 mark phase를 여러 작은 chunk로 나눔.
+- **Parallel/Concurrent Compaction**: page별 evacuation 병렬화.
+- **Lazy Sweeping**: 매 sweep을 allocation 시점까지 지연.
+- **Black Allocation**: 매 marking 중 새 alloc은 black (skip).
+
+### 매 write barrier 역할
+- 매 mutator가 마크된 object → 비마크 object 참조 추가 시 dirty card 표시.
+- 매 concurrent marker가 stale graph 처리.
+
+### 매 응용
+1. Chrome — main thread jank 감소, smooth 60fps scroll.
+2. Node.js — large heap server에서 long pause 제거.
+3. Electron/VSCode — GUI responsiveness 유지.
+
+## 💻 패턴
+
+### Orinoco effect 측정 (Node.js)
+```bash
+# Major GC pause 분포
+node --trace-gc --trace-gc-verbose app.js 2>&1 \
+  | grep "Mark-" | awk '{print $5}' \
+  | sort -n | uniq -c
+# 2026 V8: 대부분 < 1ms, occasional 5ms
+```
+
+### Disable concurrent marking (compare)
+```bash
+node --no-concurrent-marking --trace-gc app.js
+# pause time 명백히 증가 (10-50ms 종종)
+```
+
+### Per-isolate GC stats
+```javascript
+import { getHeapStatistics } from 'node:v8';
+
+const before = getHeapStatistics();
+heavyWorkload();
+const after = getHeapStatistics();
+console.log('major_gc count:', after.number_of_native_contexts);
+console.log('used:', (after.used_heap_size - before.used_heap_size) / 1e6, 'MB');
+```
+
+### Performance.measureUserAgentSpecificMemory (Chrome)
+```javascript
+// In Chrome with COOP+COEP
+if (performance.measureUserAgentSpecificMemory) {
+  const result = await performance.measureUserAgentSpecificMemory();
+  console.log(result.bytes, result.breakdown);
+}
+```
+
+### Reduce concurrent-marking pressure
+```javascript
+// Avoid: huge graph mutation in tight loop
+function reseat(arr, n) {
+  for (let i = 0; i < n; i++) arr[i] = { ref: arr[(i+1) % n] };
+  // many write barriers → marker work spike
+}
+// Prefer: build once, freeze
+const frozen = Object.freeze(buildGraph());
+```
+
+### Inspect GC marking phase via perf_hooks
+```javascript
+import { PerformanceObserver } from 'node:perf_hooks';
+
+const obs = new PerformanceObserver(list => {
+  for (const e of list.getEntriesByType('gc')) {
+    if (e.detail.kind === 2 /* MARK_SWEEP_COMPACT */)
+      console.log('major GC:', e.duration.toFixed(2), 'ms');
+  }
+});
+obs.observe({ entryTypes: ['gc'] });
+```
+
+## 매 결정 기준
+| 상황 | Approach |
+|---|---|
+| Long pause complaint (UI jank) | check Orinoco enabled (default), profile |
+| Embedded V8 (custom flags) | enable concurrent + incremental marking |
+| Constrained memory (IoT) | might disable concurrent (extra worker thread) |
+| Benchmarking | report w/ default flags + GC trace |
+
+**기본값**: 매 default flags (Orinoco on) — 매 manual disable 회피.
+
+## 🔗 Graph
+- 부모: [[Garbage_Collection]] · [[V8_엔진_힙_아키텍처|V8 Heap Architecture]]
+- 변형: [[Incremental_Marking]] · [[Concurrent_Marking]] · [[Mark-Sweep]]
+- 응용: [[Old_Space]] · [[Pointer_Compression]] · [[Write Barrier|Write_Barrier]]
+- Adjacent: [[Generational_Hypothesis]] · [[Snapshots]] · [[Multi-threaded Architecture]]
+
+## 🤖 LLM 활용
+**언제**: V8 GC internals 학습, Node.js/Chrome perf 분석, GC pause 회귀 추적.
+**언제 X**: non-V8 runtime (Hermes는 별도 GC), Java/Go GC (G1/ZGC/Shenandoah는 다른 design).
+
+## ❌ 안티패턴
+- **Disabling concurrent marking blindly**: 매 measurement 없이 — 보통 perf 악화.
+- **Huge mutation in hot loop**: 매 write barrier overload.
+- **Forcing `global.gc()` 빈번**: 매 production 절대 X — Orinoco가 알아서 함.
+- **Confusing minor (scavenge) and major (mark-sweep)**: 매 trace 해석 오류.
+
+## 🧪 검증 / 중복
+- Verified (V8 blog "Orinoco" series 2016-2019, V8 source `src/heap/`, Mathias Bynens & Benedikt Meurer talks 2017-2020).
+- 신뢰도 A.
+
+## 🕓 Changelog
+| 날짜 | 변경 |
+|---|---|
+| 2026-05-08 | Phase 1 |
+| 2026-05-10 | Manual cleanup — Orinoco GC project (concurrent/parallel/incremental) |