Total Processor Time is the average percentage of time that all processors on the computer are executing non-idle threads. ...

% Total Processor Time is the average percentage of time that all processors on the computer are executing non-idle threads.   This counter was designed as the primary indicator of processor activity on multiprocessor computers.  It is equal to the sum of Process: % Processor Time for all processors, divided by the number of processors.  It is calculated by summing the time that all processors spend executing the thread of the Idle process in each sample interval, subtracting that value from 100%, and dividing the difference by the number of processors on the computer.  (Each processor has an Idle thread which consumes cycles when no other threads are ready to run). For example, on a multiprocessor computer, a value of 50% means that all processors are busy for half of the sample interval, or that half of the processors are busy for all of the sample interval.  This counter displays the average percentage of busy time observed during the sample interval.  It is calculated by monitoring the time the service was inactive, and then subtracting that value from 100%.