https://kuntalchandra.wordpress.com/2015/10/10/install-apache-bench-ubuntu-14-04/
https://www.garron.me/en/go2linux/how-benchmark-stress-your-apache-nginx-or-iis-server.html http://tales.itnobody.com/2011/12/ab-apache-bench-understanding-and-getting-tangible-results.html