PHP：如何大致模拟sys_getloadavg（）

I am trying to resize and optimize about 1 million huge pictures on a live server. And although it is not a shared server my provider (domainfactory) does not support any of the load checks I am aware of:

• PHPs sys_getloadavg() returns array("0.00", "0.00", "0.00")
• Unix's top will return "load average: 0.00, 0.00, 0.00"
• The same applies to Unix's uptime command

Now I am looking for a way to get a comparable result. Even if it means...

1. ... that I have to put more load on the server (e.g. by dummy CPU jobs) and
2. ... that the results are only rough estimates.

Can this be done? And if so: how?