Since the original version of Windows NT, system software such as IIS, SQL Server, and MSMQ have reported runtime information through the Performance Monitor. This utility gives system administrators a quick view of the current utilization of the system -- from things like the amount of processor power and memory being used, to the number of database requests each second. Creating "Perfmon" counters in your own applications shows system administrators what your application is doing, and can also provide useful business analysis data. In this article, Matthew Reynolds looks at how performance counters work in .NET, and guides you through the creation of a reusable library that makes using performance counters a little easier.