Chip-MultiProcessors (CMP) introduce complexities when accounting CPU utilization to processes because the progress done by a process during an interval of time highly depends on the activity of the other processes it is coscheduled with. We propose a new hardware CPU accounting mechanism to improve the accuracy when measuring the CPU utilization in CMPs and compare it with previous accounting mechanisms. Our results show that currently known mechanisms lead to a 16% average error when it comes to CPU utilization accounting. Our proposal reduces this error to less than 3% in a modeled 8-core processor system.