code: function(cb) {
    fs.readFile("/proc/" + process.pid + "/stat", function(err, data) {
      if (err) {
        return cb(err);
      }
      var timeOfRead = Date.now();
  
      var elems = data.toString().split(' ');
      var utime = parseInt(elems[13]);
      var stime = parseInt(elems[14]);
  
      cb(undefined, utime + stime, timeOfRead);
    });
  }
docs: http://stackoverflow.com/a/7774034/2829381