1. A graphics processing system configured to track per-tile event counts in a tile-based architecture, the graphics processing system comprising: a tiling unit configured to: cause a screen-space pipeline to load a first count value associated with a first cache tile into a count memory, cause the screen-space pipeline to process a first set of primitives that intersect the first cache tile, cause the screen-space pipeline to store a second count value, cause the screen-space pipeline to process a second set of primitives that intersect the first cache tile, and cause the screen-space pipeline to store a third count value, wherein at least one primitive in the first set of primitives and at least one primitive in the second set of primitives cause the screen-space pipeline to detect an event type and increment the count memory.