eventloop-latency

This lib is part of Bronitor project. It counts eventloop latency using process.hrtime

Requirements

Code written using ECMAScript 2015. It tested on node >= 4

Use babel if, you want to use it on node < 4

Installation

$ npm i eventloop-latency --production

Usage

const EL = require('eventloop-latency'),
    interval = 5000, 
    hrInterval = 10, 
    monitoring = new EL(interval, hrInterval);
   
monitoring.start(true);   
monitoring.on('data', (data) => {
  console.log(data); // [49, 27, ..., 144, 923]
});
monitoring.stop();
  
monitoring.start();
setInterval(() => {
   console.log(monitoring.countLatency()); // [149, 7, ..., 14, 92]
}, 1000) 

Docs

• monitoring - main object, eventemitter, takes two options:
  • iterval - interval in ms for emitting 'data' event, optional, defaults to 5000 ms
  • hrIntreval - interval in ms using to count latency, should be in range 10-100, optional, defaults to 10 ms
• start() - function, that start monitoring, takes option:
  • enableEmit - if true, monitoring will emit "data" event, else function countLatency() is used to get latency info
• stop() - function, that stop monitoring
• countLatency() - function, that return array with latency
• "data" event - returns array of latency in µs(microseconds, 10e-6 s) during the interval

Examples

You can see small example in demos/server.js. Run it:

$ npm run-script demo

Tests

To run the test suite, first install the dependencies, then run npm test:

$ npm install
$ npm test

License

MIT