Node.js 利用多进程优化 CPU 密集型计算

function fibonacci(n) {
 if (n == 0 || n == 1) {
  return n;
 } else {
  return fibonacci(n - 1) + fibonacci(n - 2);
 }
}

let startTime = Date.now();
let totalCount = 500;
let completedCount = 0;
let n = 35;

for (let i = 0; i < totalCount; i++) {
 fibonacci(n);
 completedCount++;
 console.log(`process: ${completedCount}/${totalCount}`);
}
console.log("👏 👏 👏 👏 👏 👏 👏 👏 👏 👏");
console.info(`任务完成，用时: ${Date.now() - startTime}ms`);
console.log("👏 👏 👏 👏 👏 👏 👏 👏 👏 👏");

const cluster = require("cluster");
const numCPUs = require("os").cpus().length;

// 设置子进程执行程序
cluster.setupMaster({
 exec: "./worker.js",
 slient: true
});

function run() {
 // 记录开始时间
 const startTime = Date.now();
 // 总数
 const totalCount = 500;
 // 当前已处理任务数
 let completedCount = 0;
 // 任务生成器
 const fbGenerator = FbGenerator(totalCount);

 if (cluster.isMaster) {
  cluster.on("fork", function(worker) {
   console.log(`[master] : fork worker ${worker.id}`);
  });
  cluster.on("exit", function(worker, code, signal) {
   console.log(`[master] : worker ${worker.id} died`);
  });

  for (let i = 0; i < numCPUs; i++) {
   const worker = cluster.fork();

   // 接收子进程数据
   worker.on("message", function(msg) {
    // 完成一个，记录并打印进度
    completedCount++;
    console.log(`process: ${completedCount}/${totalCount}`);

    nextTask(this);
   });

   nextTask(worker);
  }
 } else {
  process.on("message", function(msg) {
   console.log(msg);
  });
 }

 /**
  * 继续下一个任务
  *
  * @param {ChildProcess} worker 子进程对象，将在此进程上执行本次任务
  */
 function nextTask(worker) {
  // 获取下一个参数
  const data = fbGenerator.next();
  // 判断是否已经完成，如果完成则调用完成函数，结束程序
  if (data.done) {
   done();
   return;
  }
  // 否则继续任务
  // 向子进程发送数据
  worker.send(data.value);
 }

 /**
  * 完成，当所有任务完成时调用该函数以结束程序
  */
 function done() {
  if (completedCount >= totalCount) {
   cluster.disconnect();
   console.log("👏 👏 👏 👏 👏 👏 👏 👏 👏 👏");
   console.info(`任务完成，用时: ${Date.now() - startTime}ms`);
   console.log("👏 👏 👏 👏 👏 👏 👏 👏 👏 👏");
  }
 }
}

/**
 * 生成器
 */
function* FbGenerator(count) {
 var n = 35;
 for (var i = 0; i < count; i++) {
  yield n;
 }
 return;
}

module.exports = {
 run
};

function fibonacci(n) {
 if (n == 0 || n == 1) {
  return n;
 } else {
  return fibonacci(n - 1) + fibonacci(n - 2);
 }
}

// 接收主线程发送过来的任务，并开始查找斐波那契数
process.on("message", n => {
 var res = fibonacci(n);
 // 查找结束后通知主线程，以便主线程再度进行任务分配
 process.send(res);
});
入口代码：cluster.js
// 引入主线程js，并执行暴露出来的run方法
const master = require("./master");
master.run();