Understanding the Multiple Processor Counters

Some Performance Monitor counters were designed for single processor systems and might not be entirely accurate for multiprocessor systems.

For example, on a multiprocessor computer, a process can (and often does) use more than the equivalent of 100% processor time on one processor. Although it is limited to 100% of any single processor, its threads can use several processors, totaling more than 100%. However, the Process: % Processor Time counter never displays more than 100%. To determine how much total processor time a process is getting, chart the Thread: % Processor Time counter for each of the process's threads.

Use the following counters to monitor multiple processor computers.

Counter

Use

System: %Total Processor Time

A measure of processor activity for all processors in the computer.

This counter sums average non-idle time of all processors during the sample interval and divides it by the number of processors.

For example, if all processors are busy for half of the sample interval, on average, it displays 50%. It also displays 50% if half of the processors are busy for the entire interval, and the others are idle.

System: Processor Queue Length

The length of the processor queue. There is a single queue, even when there are many processors.

Processor: % Processor Time

A measure of the processor time of each processor.

Process: % Processor Time

The sum of processor time on each processor for all threads of the process.

Thread: % Processor Time

The amount of processor time for a thread.