How to calculate the created load on the server?

Question

Performance evaluation

There is a need to create one server for dozens of clients to process their complex requests, for example, so that the client does not load its server. For example, a client needs to update data with a volume of 500,000 records, we hang this script on our dedicated powerful server, and in this case, the complex process is processed inside the dedicated server. Perhaps another is great, did not google. Well, the question itself is the following, how can you calculate the load created by one client? Then, for example, to bring it into the database or track whether it passes through the limits? which are determined on it.
The ultimate goal is to understand how much server resource one client eats.

Answer 1

xhprof, blackfire