Windows 2000 Performance Guide

Performance Monitoring Overhead

Now that we understand how the Windows 2000 performance monitoring interface works, we can tackle the issue of overhead. “What does all this Windows 2000 performance monitoring cost?” is a frequent question. Naturally, you want to avoid any situation where performance monitoring is so costly in its use of computer resources that it drastically influences the performance of the applications you care about. Performance monitoring must be part of the solution, not part of the problem. As long as the overhead of performance monitoring remains low, we can accept it as part of the cost of doing business. With performance monitoring, when something goes wrong, we at least have a good chance of finding out what happened. However, as we have already observed, logging performance data to a text file using System Monitor can be very CPU-intensive. When a logging session that is writing a text format data file is active, it can consume so much CPU time that it affects the performance of other applications you are trying to run.

Understanding how much overhead is involved in Windows 2000 performance monitoring is not a simple proposition. It helps to break up the overhead considerations into three major areas of concern:

• The overhead involved in measuring Windows 2000

• The overhead involved in gathering performance monitor data

• The overhead involved in analyzing and other post-processing of the measurement data

We discuss these three areas of concern in the ...