Node.js 怎么利用多核？cluster、child_process、worker_threads 有什么区别？

// server.mjs
import cluster from 'node:cluster'
import http from 'node:http'
import { availableParallelism } from 'node:os'

if (cluster.isPrimary) {
  // 主进程：按 CPU 核数启动 worker，自己不处理请求
  for (let i = 0; i < availableParallelism(); i++) cluster.fork()

  cluster.on('exit', (worker, code, signal) => {
    // 主动 disconnect 的（如逐个重启时）由重启逻辑负责补位，这里只补意外退出的
    if (worker.exitedAfterDisconnect) return
    console.log(`worker ${worker.process.pid} 意外退出（${signal ?? code}），重新启动一个`)
    cluster.fork()
  })
} else {
  // worker：各自是独立的进程，监听同一个端口
  http.createServer((req, res) => {
    res.end(`由进程 ${process.pid} 处理\n`)
  }).listen(3000)
}

// fib-worker.mjs：在 Worker 线程里执行
import { parentPort, workerData } from 'node:worker_threads'

const fib = (n) => (n < 2 ? n : fib(n - 1) + fib(n - 2))
parentPort.postMessage(fib(workerData))

// main.mjs
import { Worker } from 'node:worker_threads'

function runFib(n) {
  return new Promise((resolve, reject) => {
    const worker = new Worker(new URL('./fib-worker.mjs', import.meta.url), { workerData: n })
    worker.once('message', resolve)
    worker.once('error', reject)
    worker.once('exit', (code) => {
      if (code !== 0) reject(new Error(`Worker 异常退出，退出码 ${code}`))
    })
  })
}

const timer = setInterval(() => console.log('主线程没有被阻塞'), 200)
console.log('fib(40) =', await runFib(40))
clearInterval(timer)