Есть прекрасный сервис https://tools.pingdom.com/... Когда-нибудь я напишу по нему подробный обзор

Тестирование утилитой ab (Apache Benchmark)

ab -c 8 -n 10000 http://mail.ru/

8 потоков, 10000 запросов

Server Software:        nginx/1.15.2
Server Hostname:        mail.ru
Server Port:            80

Document Path:          /
Document Length:        53960 bytes

Concurrency Level:      8
Time taken for tests:   186.452 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      542200000 bytes
HTML transferred:       539600000 bytes
Requests per second:    53.63 [#/sec] (mean)
Time per request:       149.161 [ms] (mean)
Time per request:       18.645 [ms] (mean, across all concurrent requests)
Transfer rate:          2839.83 [Kbytes/sec] received

Результат теста: 53.63 страниц в секунду, на тестирование затрачено 186.452 секунд.

loader.io:

loader.io-load-testing-application
https://loader.io