I don't understand very well the behavior of my web application. It's a php web application running on Nginx. I tried to test some simple page and I get:
ab -n 5000 -c 500 http://xxx
Req per sec: 600
Time per req 1.6 ms (mean across requests)
ab -n 5000 -c 100 http://xxx
Req per sec: 50
Time per req 20 ms (mean across requests)
I probably don't understand the result. I thought that increasing the concurrency 10 times I would see a dramatic decrease in average request performance...where am I wrong?