UI processing time
Applies to: 
Visual Studio 
Visual Studio for Mac
Note
This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
These segments in the timeline are associated with blocking times that are categorized as UI Processing. This implies that a thread is pumping Windows messages or performing other user interface (UI) work. During this time, a thread has been blocked in an API that the Concurrency Visualizer is counting as UI Processing. APIs such as GetMessage() and MsgWaitForMultipleObjects() fall into this group.
If no pre-defined blocking API is identified, review the call stacks and profile reports to determine the underlying causes of delay.
The UI Processing category helps you understand the responsiveness of GUI applications, and is desirable in applications that depend on UI responsiveness. For example, if the UI thread in an application achieves 100% time in UI Processing, it is probably responsive. However, if the UI thread spends considerable time in other categories, look for the root causes and consider options for reducing non-UI categories on that thread.