Event Tracing for Windows (ETW) is a high-speed tracing facility provided by the Windows Operating System which was first introduced in Windows 2000.
Event Tracing for Windows (ETW) is a general-purpose, high-speed tracing facility provided by the Windows operating system. Using a buffering and logging mechanism implemented in the kernel, ETW provides a tracing mechanism for events raised by both user-mode applications and kernel-mode device drivers.
Additionally, ETW gives you the ability to enable and disable logging dynamically, making it easy to perform detailed tracing in production environments without requiring reboots or application restarts. The logging mechanism uses per-processor buffers that are written to disk by an asynchronous writer thread. This allows large-scale server applications to write events with minimum disturbance.
ETW is the core tracing facility in Windows on top of which both the Event Log and WPP are built.
ETW was first introduced on Windows 2000. Since then, various core OS and server components have adopted ETW to instrument their activities, and it's now one of the key instrumentation technologies on Windows platforms.
On Windows Vista, ETW has gone through a major upgrade, and one of the most significant changes is the introduction of the unified event provider model and APIs. In short, the new unified APIs combine logging traces and writing to the Event Viewer into one consistent, easy-to-use mechanism for event providers. At the same time, several new features have been added to improve developer and end user experience.