A look at the Xbox 360's 'procedural synthesis'
Jon Stokes has written up an overview of how the Xbox 360 may handle
certain aspects of the gaming environment. The first part of the article is largely a discussion of the threading model we noted when it was revealed in a Microsoft patent application
some months ago. The Xbox 360's three CPU cores will feed geometry data to the GPU after doing the processing work for a mix of common graphics techniques like higher-order surfaces, geometry instancing, dynamic level of detail, and vertex skinning with keyframe interpolation. That list may read like something from a four-year history of the Radeon, but the real innovation here is that these tasks will be offloaded to the Xbox 360's CPU cores via multiple threads.
We now know that the Xbox 360 will contain a GPU with an immense amount of vertex processing power thanks to its unified shader units, so its CPUs will have to be very capable in order to complement it well. To that end, Stokes points out that the Xenon processor's three cores will be able to partition off parts of their L2 caches for use as FIFO buffers for streaming data to the GPU. This scheme should allow the Xbox 360 to keep its GPU fed with copious amounts of geometry data, if it all works well. Stokes promises a second article that delves into the architecture of the Xenon CPU, and that will likely address some of the other ways the Xenon has been optimized for gaming performance.