For a quick way to determine how your website/application responds to simultaneous requests, try the ApacheBench application.
ApacheBench can be installed on Ubuntu by installing the apache2-utils package.
sudo apt install apache2-utils
Once the apache-utils package is installed, run the ab command to test your website.
ab -n 100 -c 10 http://example.com
In the above example,
- -n specifies the number of requests to run
- -c specifies how many requests to run concurrently