We are devloping an ERP. There is a notion called "Head Room" for performance testing. As per our understanding, head room stands for the amount of free CPU/Memory(RAM).

Suppose if I say, the head room should be of 10%. Does it mean that maximum utilization of CPU should be 90 % irrelvant of other running applications.

But CPU is allocated to different applications running on the PC as per the algorithm used by OS. How can we restrict ERP or other applications to use CPU up to 90% ?

Please guide us.