2nd/10_Wiki/Topics/Architecture/Multi-threaded Architecture.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-multi-threaded-architecture	Multi-threaded Architecture	10_Wiki/Topics	verified	self	Multithreading Concurrent Architecture MT Architecture	none	A	0.9	applied	architecture concurrency threading performance		2026-05-10	pending	language framework cpp stdthread-tbb-rayon

Multi-threaded Architecture

매 한 줄

"매 work를 multiple threads에 분산하여 throughput · responsiveness를 동시에 확보.". 1990s SMP era에서 출발하여 2026 현재 manycore (Apple M4 Max 16-core, AMD Threadripper 96-core), GPU offload, async/await coroutine model이 주류. Game engine · server · ML inference · browser engine 모두 multi-threaded 설계가 default.

매 핵심

매 thread model 종류

• OS thread (1:1): pthread, std::thread — kernel-scheduled, expensive context switch.
• Green thread / fiber: Go goroutine, Java 21 virtual thread — userland scheduler, M:N mapping.
• Coroutine / async task: C++20 coroutine, Rust async, Kotlin coroutine — stackless, await-resume.
• Task-based: Intel TBB, .NET TPL, Apple GCD — work-stealing scheduler, no thread management.

매 architectural pattern

• Producer-consumer: bounded queue로 backpressure.
• Pipeline: stage별 thread, ring buffer로 연결 (LMAX Disruptor).
• Fork-join: divide & conquer, work-stealing.
• Actor: 매 message passing (Akka, Erlang, Pony) — no shared state.
• Data parallelism: SIMD + thread pool — Rayon par_iter(), OpenMP #pragma omp parallel for.

매 응용

1. Game engine — render thread + game thread + audio thread + IO thread.
2. Browser — process-per-tab + GPU process + utility processes.
3. Database — connection pool + worker threads + background flush.

💻 패턴

Thread pool with work queue (C++20)

#include <thread>
#include <queue>
#include <mutex>
#include <condition_variable>
#include <functional>

class ThreadPool {
  std::vector<std::jthread> workers;
  std::queue<std::function<void()>> tasks;
  std::mutex mtx;
  std::condition_variable cv;
  bool stop = false;
public:
  explicit ThreadPool(size_t n) {
    for (size_t i = 0; i < n; ++i)
      workers.emplace_back([this](std::stop_token st) {
        while (!st.stop_requested()) {
          std::function<void()> task;
          {
            std::unique_lock lk(mtx);
            cv.wait(lk, [&]{ return stop || !tasks.empty(); });
            if (stop && tasks.empty()) return;
            task = std::move(tasks.front()); tasks.pop();
          }
          task();
        }
      });
  }
  template<class F> void submit(F&& f) {
    { std::lock_guard lk(mtx); tasks.emplace(std::forward<F>(f)); }
    cv.notify_one();
  }
};

Rust Rayon data parallelism

use rayon::prelude::*;

fn process_batch(items: &[Item]) -> Vec<Result> {
    items.par_iter()
        .filter(|i| i.valid())
        .map(|i| expensive_compute(i))
        .collect()
}
// auto: work-stealing across all cores

Go goroutine + channel (fan-out / fan-in)

func pipeline(input <-chan Job) <-chan Result {
    out := make(chan Result, 100)
    var wg sync.WaitGroup
    for i := 0; i < runtime.NumCPU(); i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            for job := range input {
                out <- process(job)
            }
        }()
    }
    go func() { wg.Wait(); close(out) }()
    return out
}

Lock-free SPSC ring buffer

template<typename T, size_t N>
class SPSCQueue {
  alignas(64) std::atomic<size_t> head{0};
  alignas(64) std::atomic<size_t> tail{0};
  T buffer[N];
public:
  bool push(T v) {
    auto t = tail.load(std::memory_order_relaxed);
    auto next = (t + 1) % N;
    if (next == head.load(std::memory_order_acquire)) return false;
    buffer[t] = std::move(v);
    tail.store(next, std::memory_order_release);
    return true;
  }
};

Game engine 3-thread architecture

// Main thread: input + game logic
// Render thread: GPU command buffer
// IO thread: asset streaming
struct FrameSync {
  std::atomic<uint64_t> game_frame{0};
  std::atomic<uint64_t> render_frame{0};
  std::counting_semaphore<2> render_ready{0};
};
// double-buffer scene state to allow N+1 game tick parallel with N render

매 결정 기준

상황	Approach
CPU-bound, divisible work	Rayon / OpenMP / TBB
IO-heavy (10k+ connections)	async/await (Tokio, asyncio, Node)
Real-time game loop	dedicated threads + lock-free queue
Mixed workload	task-based (TBB, GCD)
Simple parallel-for	thread pool + work queue
Distributed across machines	actor (Akka) or message queue

기본값: task-based scheduler (TBB/Rayon/Tokio) — manual thread management 회피.

🔗 Graph

• 부모: Concurrent_Rendering · Distributed-Systems
• 변형: Fiber_Architecture
• 응용: Game_Loop · V8 엔진 힙 아키텍처 · Browser
• Adjacent: SharedArrayBuffer_보안_이슈와_Cross-Origin_Isolation · Memory_Leaks

🤖 LLM 활용

언제: throughput-critical workload, multi-core utilization, real-time game/server, ML inference batching. 언제 X: simple sequential script, IO-light short-lived task, single-core embedded — 매 overhead 큼.

❌ 안티패턴

• Shared mutable state without sync: data race · UB.
• Coarse global lock: 매 single-thread보다 느림 (lock contention).
• Thread per request (10k+): stack memory 폭발 — async 또는 thread pool 사용.
• busy-wait spin: CPU 100% 소모 — condition variable / semaphore.
• False sharing: 같은 cache line의 다른 atomic — alignas(64) cache padding.

🧪 검증 / 중복

• Verified (Herb Sutter "The Free Lunch Is Over" 2005, Intel TBB docs, Rust async book 2026).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — full content (thread models, patterns, decision matrix)