gistfile1.js

var TIME_INTERVAL = 1000;

var oldTime = process.hrtime();

var histogram = probe.histogram({
  name        : 'Loop delay',
  measurement : 'mean',
  unit        : 'ms'
});

setInterval(function() {
  var newTime = process.hrtime();
  var delay = (newTime[0] - oldTime[0]) * 1e3 + (newTime[1] - oldTime[1]) / 1e6 - TIME_INTERVAL;
  oldTime = newTime;
  histogram.update(delay);
}, TIME_INTERVAL);