Hi there, this is Mark with the Windows Performance Team. This post is a quick introduction to a new performance tracing tool called XPerf. Moving forward with Windows Vista and Windows Server 2008, this powerful tool will hopefully be utilized more often. XPerf is part of the Windows Performance Toolkit (WPT) which can be downloaded from the Microsoft web site.

XPerf is designed for Windows Vista and Windows Server 2008, but will run on Windows XP and Windows Server 2003 by copying Xperf.exe and Perfctrl.dll to the target machine. XPerf uses ETW (Event Tracing for Windows) and is very low overhead, requiring only about 1500-2000 clock cycles per log. As an example, 20,000 calls per second is less than 2% CPU on a 2.0 GHz processor. While the data collection is running, the XPerf tools are not even loaded - the kernel itself is collecting the data. All analysis is done in post processing. Since Xperf is ETW based, sample profiling can be started and stopped at any time, without stopping or restating even a single process. You can profile anything at any time on any system. The traces are logged in a circular fashion, based on the buffer size that is set.