CPU Utilization of Android dual core device

CPU Utilization of Android dual core device

In android mobile devices, nowadays many models support Dual core
processors. If i want to measure the CPU utilization using top command i
get a single value as 40% or anything.
Consider an example - 50%. Does this mean any of the following ?
Core 1 is completely utilized and Core 2 is free. So 50% out of 100% is
utilized.
50% of Core 1 and 50% of Core 2 is utilized.
How do i say, my application is consuming better CPU ? How do i measure it ?