This section details metrics related to general GPU performance characteristics. Subsequent topics contain metrics that pertain to specific fixed function (FF) units within the GPU.
Some of the common GPU metrics pertain to execution unit (EU) performance. The EUs are the general-purpose processing cores within the GPU that perform various compute tasks for one or more stages of the rendering pipeline. Each EU can execute multiple tasks simultaneously, with each EU maintaining a list of software threads that are assigned for execution on that EU. As threads stall (for various reasons, including memory fetches), the EU is able to quickly switch to another thread, which in many cases means that each EU is able to keep executing without stalling during the rendering of a frame. Therefore, for maximum rendering efficiency you should typically strive to keep all EUs busy 100% of the time. Note that in this document, the term “thread” may refer to either software threads or hardware threads, and the specific context will usually help clarify which term is intended.