How to measure switching losses?

Question

System administration

Let's say there is a pack of servers (so far virtual).
HAProxy → nginx → static
I can't figure out how to measure the speed of switching packets passing through this group of interfaces / machines. Perhaps another server will appear in the chain. How are tails measured?

Answer 1

And what prevents you from requesting a static page of one letter and measuring the time between sending GET and receiving 200?