experiment on http.globalAgent.maxSockets of Node.js

README.md

It was fastest without maxSockets until the client gets Error: connect ECONNRESET 127.0.0.1:8080. maxSockets avoided the error but didn't work for performance.

client.js

const http = require('http');

const REQ_COUNT = 10000;

http.globalAgent.maxSockets = 10000;

// http.globalAgent.maxSockets = Number.POSITIVE_INFINITY;
const request = () => new Promise((resolve, reject) => {
  http.get('http://localhost:8080', (res) => {
    let buffer = '';
    res.setEncoding('utf-8');
    res.on('readable', (chunk) => {
      buffer += res.read();
    });
    res.on('end', () => {
      resolve(buffer);
    });
    res.on('error', (e) => {
      reject(e);
    });
  });
});

const timeout = (ms) => new Promise((resolve) => {
  setTimeout(resolve, ms);
});

const start = process.hrtime();
const promises = Array(REQ_COUNT).fill(0)
  .map(() => timeout(100 * Math.random()).then(request));

Promise.all(promises)
  .then(() => {
    const [s, ns] = process.hrtime(start);
    console.log('done', REQ_COUNT, s * 1000.0 + ns / 1000000.0, 'ms');
  })
  .catch((e) => {
    console.error('error', e);
  });

server.js

const http = require('http');

const server = http.createServer((req, res) => {
  const timeout = 30 + Math.floor(Math.random() * 100);
  setTimeout(() => {
    res.writeHead(200, {
      'Content-Type': 'application/json',
    });
    res.end(JSON.stringify({ hello: 'world', timeout }));
  }, timeout);
});
server.listen(8080, () => {
  const { address, port } = server.address();
  console.log(`Listening on ${address}:${port}`);
});