How to test a web application for 100 users and measure the memory usage

I am building a Laravel CMS web application, and am wishing to know the memory usage per user, and simulate up to 250 users and measure the associated memory usage.

I have looked at web-stress tools, but they do not offer a memory usage output (that I can see).

Is there a way to measure the memory usage of a Laravel web application, and is there a way to simulate multiple users drawing on resources at once?