The OpenCL Performance Marker (CLPerfMarker) library provides a simple host-code instrumentation API that can help users to analyze their OpenCL applications.
It allows users to instrument their code with calls to clBeginPerfMarkerAMD() and clEndPerfMarkerAMD(). These calls are then used by the APP Profiler to annotate the host-code timeline in a hierarchical way.
The following image shows an application that has been instrumented with this API. In the image, the rows labeled OpenGL represent performance markers added to the host code.