mathjax-node experiment with forking child processes

child.js

const mathjax = require('mathjax-node');
const typeset = mathjax.typeset;

process.on('message', function(m) {
    if (m === 'exit') {
      // empty typeset to push exit on MathJax's queue (else we'd terminate too soon)
      typeset({"math": "", "format": "TeX", "mml":true}, function(result) {
          process.send('exit');
      })
    } else {
        var data = JSON.parse(m);
        typeset(data, function(result) {
            process.send(result.mml);
        })
    }
});

parent.js

const cp = require('child_process');
const os = require('os');
// const threads = os.cpus().length;
const threads = 2;
const n = 1000;
const start = new Date();

// 1,000 nodes (results in ms)
//
// 1 thread  3559, 4161, 4001
// 2 threads 3075, 2976, 3046
// 3 threads 3403, 3331, 3399
// 4 threads 3928, 3653, 3633
//
// 5,000 nodes
// 1 thread  15367
// 2 threads 11577
// 3 threads 11280
// 4 threads 11854
//
// 10,000 nodes
//
// 1 thread  34345, 30004, 29587
// 2 threads 19238, 18948, 21973
// 3 threads 18850, 19434, 19379
// 4 threads 20117, 19744, 19551
// SVG 2: 19347, 4:  19347, 3: 17643


const messaging = function(m, child) {
  // Receive results from child process
  console.log('received: ' + m);
  if (m === 'exit') {
    child.kill()
    var end = new Date() - start;
    console.log(end);
  }
}

let children = {};
for (let k = 0; k < threads; k++){
  let child = cp.fork('./child.js');
  children[k] = child;
  child.on('message', function(m){
    messaging(m, child);
  });
}

const mjprocess = function(i){
  let k = i%threads;
  let child = children[k];
  child.send('{"math": "\\\\alpha' + i + '", "format": "TeX", "mml":true}');
  if (i+threads > n-1) child.send('exit');
}


for (let i=0; i < n; i++){
  mjprocess(i);
}