Perf mon _total vs <All instances>

In the Windows performance monitor tool. 开发者_如何学编程What's the difference between _Total and , when selecting instances for a counter?

I believe the _Total counter is simply an aggregate for situations where there are multiple instances of the same counter. In certain cases, like Processor - % Process Time, it provides an average across all the instances.

Selecting the 'All instances' option is just a shortcut way of including all the instance counters (saving you the trouble of selecting each one individually).