We are doing some load testing on a PHP (Kohana) application. One funny thing we noticed is that each request seems to be creating 4 process each time and increases the load on the sever by 4 times. And when there are, for example, 500 users per second hitting it acts as 500*4.
I really don't understand what could be creating all these processes. My understanding is that each PHP request creates one thread, it shouldn't be creating processes, especially not 4. Could it be an Apache issue? Or PHP issue?
I didn't find any information about this on Google. Any suggestion on what could be causing this problem would be appreciated.