Pomegranate: a fully scalable graphics architecture

Pomegranate is a parallel hardware architecture for polygon rendering that provides scalable input bandwidth, triangle rate, pixel rate, texture memory and display bandwidth while maintaining an immediate-mode interface. The basic unit of scalability is a single graphics pipeline, and up to 64 such units may be combined. Pomegranate's scalability is achieved with a novel “sort-everywhere” architecture that distributes work in a balanced fashion at every stage of the pipeline, keeping the amount of work performed by each pipeline uniform as the system scales. Because of the balanced distribution, a scalable network based on high-speed point-to-point links can be used for communicating between the pipelines. Pomegranate uses the network to load balance triangle and fragment work independently, to provide a shared texture memory and to provide a scalable display system. The architecture provides one interface per pipeline for issuing ordered, immediate-mode rendering commands and supports a parallel API that allows multiprocessor applications to exactly order drawing commands from each interface. A detailed hardware simulation demonstrates performance on next-generation workloads. Pomegranate operates at 87-99% parallel efficiency with 64 pipelines, for a simulated performance of up to 1.10 billion triangles per second and 21.8 billion pixels per second.