用NodeJS實現集群計算

    var cluster = require('cluster');

    var http = require('http');

    var numCPUs = require('os').cpus().length;


if (cluster.isMaster) {  
  // Fork workers.  
  require('os').cpus().forEach(function(){  
    cluster.fork();  
  });  
  // In case the worker dies!  
  cluster.on('exit', function(worker, code, signal) {  
    console.log('worker ' + worker.process.pid + ' died');  
  });  
  // As workers come up.  
  cluster.on('listening', function(worker, address) {  
    console.log("A worker with #"+worker.id+" is now connected to " +\  
     address.address +\  
    ":" + address.port);  
  });  
  // When the master gets a msg from the worker increment the request count.  
  var reqCount = 0;  
  Object.keys(cluster.workers).forEach(function(id) {  
    cluster.workers[id].on('message',function(msg){  
      if(msg.info && msg.info == 'ReqServMaster'){  
        reqCount += 1;  
      }  
    });  
  });  
  // Track the number of request served.  
  setInterval(function() {  
    console.log("Number of request served = ",reqCount);  
  }, 1000);  

} else {  
  // Workers can share the same port!  
  require('http').Server(function(req, res) {  
    res.writeHead(200);  
    res.end("Hello from Cluster!");  
    // Notify the master about the request.  
    process.send({ info : 'ReqServMaster' });  
  }).listen(8000);  
}  </pre><br />

在一個4核的計算機上，輸出如下：

 
Number of request served =  0  
A worker with #2 is now connected to 0.0.0.0:8000  
A worker with #4 is now connected to 0.0.0.0:8000  
A worker with #1 is now connected to 0.0.0.0:8000  
A worker with #3 is now connected to 0.0.0.0:8000  
Number of request served =  0  
...  
Number of request served =  2  
..  
Number of request served =  4  
...  
Number of request served =  6 
來自：http://blog.csdn.net/chszs/article/details/8054773