get response time with curl
$ curl -o /dev/null -s -w 'Total: %{time_total}s\n' https://www.changwoo.org/x1wins@changwoo.net Total: 0.432215s
$ curl -o /dev/null -s -w 'Total: %{time_total}s\n' https://www.changwoo.org/x1wins@changwoo.net Total: 0.432215s