Maximum performance for node HTTP server? - node.js

Question

I'm running a test trying to draw maximum delivery speed from a Node HTTP server. It's a simple server.
In my test I have 50K virtual clients establishing a permanent connection with the server (I run ulimit -n 99999 before). Then, upon another event, an HTTP connection to a different port, the server sends one message to each virtual client. At the end all clients receive the corresponding message.
Sending all messages takes minutes in my tests. Are there any recommendations that would help me improve these measurements so that I can send 50K messages in seconds instead of minutes?
The server is running in a m1.medium AWS instance. The idea is to improve performance with the same platform.
Copying the server code:
var http = require("http");
var connectionResponse = [];
var connectionIndex = 0;
http.createServer(function(request, response) {
console.log("Received connection " + connectionIndex);
response.setTimeout(1200000, function() {
console.log("Socket timeout");
});
connectionResponse[connectionIndex] = response;
connectionIndex++;
}).listen(8888);
http.createServer(function(request, response) {
console.log("8887 connected - Will respond");
response.writeHead(200, {"Content-Type": "text/plain"});
response.write("Triggered all responses");
response.end();
console.log("Begin notifications:" + new Date().toISOString());
for(var i = 0; i < connectionIndex; i++) {
connectionResponse[i].writeHead(200, {"Content-Type": "text/plain", "Content-Length": 4, "transfer-encoding" : ""});
connectionResponse[i].write("CAFE");
connectionResponse[i].end();
}
console.log("End notifications" + new Date().toISOString());
}).listen(8887);

Answer 1

Setting this http://nodejs.org/api/http.html#http_agent_maxsockets to a sufficient number
var http = require('http');
http.globalAgent.maxSockets = xxx;
var https = require('https');
https.globalAgent.maxSockets = xxx;
Using nodejs clustering module, http://nodejs.org/api/cluster.html
Now, regarding the clustering, it really depends on what you want to do. The default example can go long way before you have to tweak it. An example would be
var cluster = require('cluster');
var http = require('http');
var numCPUs = require('os').cpus().length;
if (cluster.isMaster) {
// Fork workers.
for (var i = 0; i < numCPUs; i++) {
cluster.fork();
}
cluster.on('exit', function(worker, code, signal) {
console.log('worker ' + worker.process.pid + ' died');
});
} else {
// Workers can share any TCP connection
// In this case its a HTTP server
http.createServer(function(req, res) {
res.writeHead(200);
res.end("hello world\n");
}).listen(8000);
}