Benchmarking your application is important to see how the application performs under heavier traffic and load.
Very common benchmarking tool you can use is ab.
ab -c 10 -n 1000 http://localhost/
Stage and beta environments can be sometimes closed for public with HTTP authentication. To pass username and password:
ab -c 10 -n 1000 -A username:password http://beta.example.org/
siege -c 10 -r 100 -b -i http://localhost
Apache JMeter is a more feature rich load tester.
Gatling is a load tester with GUI.
HTTP keep-alive or HTTP persistent connections greatly improve performance. In performance testing you can enable them and get better results, however these vary from one testing software to another. Good practice is to disable them and get comparable results among the above tests.