Node.js client-server timings.

client.js

const http = require("http");
const NanoTimer = require("nanotimer");   // Documentation: https://github.com/Krb686/nanotimer

function getNanoTime() {
  const t = process.hrtime(); // Documentation: https://nodejs.org/api/process.html#process_process_hrtime_time
  return t[0] * 1e9 + t[1];   // [seconds, nanoseconds]
}

const options = {
  hostname: '127.0.0.1',
  port: 3000,
  path: '/'
};

const start_time_ns = getNanoTime();
const timer = new NanoTimer();
const total_requests = 1e6;
const max_pending_requests = 1e4;
let requests_left = total_requests;
let request_counter = 0;
let pending_request = 0;

console.log("Client PID: " + process.pid);

timer.setInterval(() => {

  if (request_counter === total_requests) {
    timer.clearInterval();
    return;
  }
  if (pending_request === max_pending_requests) {
    // max_pending exeeded, waiting for next interval
    return;
  }
  if (request_counter % 1e4 === 0) {
    console.log("request_counter", request_counter);
  }

  request_counter++;
  pending_request++;

  http.get(options, res => {
    pending_request--;
    requests_left--;
    if (requests_left < 1) {
      const duration_ns = getNanoTime() - start_time_ns;
      console.log("requests_left", requests_left);
      console.log("Stopping. " + total_requests + " requests took " + duration_ns / (1e6) + " ms");
    }

  }).on("error", err => {
    console.log("error");
  });

}, "", "1u");

server.js

/*
  Limitations to TCP (I think) required me to change WAIT_TIME please read here.
  http://stackoverflow.com/questions/1216267/ab-program-freezes-after-lots-of-requests-why

  On MacOS I ran:
  sysctl -w net.inet.ip.portrange.first=32768
  sysctl -w net.inet.tcp.msl=1000
*/

const http = require("http");
const cluster = require("cluster");
const numInstances = 4;
const hostname = "127.0.0.1";
const port = 3000;

if (cluster.isMaster) {
  for (let i = 0; i < numInstances; i++) {
    cluster.fork();
  }
  cluster.on("exit", (worker, code, signal) => {
    console.log("worker with id: " + worker.process.pid + " died");
  });
} else {

  const server = http.createServer((req, res) => {
    //console.log("worker with id: " + process.pid + " handles request");
    res.statusCode = 200;
    res.setHeader("Content-Type", "text/html");
    res.end("<p>hello, world!</p>");
  });

  server.listen(port, hostname, () => {
    console.log("Server PID: " + process.pid + " running at http://" + hostname + ":" + port + "/");
  });

  server.on("error", err => {
    console.log(err);
  });
}

process.on("uncaughtException", () => {
  console.log(err);
});

I'm not sure I'm testing anything meaningful. I'm not claiming this is scientific test. Related to this thread: http://stackoverflow.com/questions/9290160/node-js-vs-net-performance#

Please comment if you see any errors.