DirectCompute

 

Microsoft DirectCompute is an application programming interface (API) that takes advantage of the massively parallel processing power of a modern graphics processing unit (GPU) to accelerate PC application performance in Microsoft Windows Vista or Windows 7. DirectCompute is part of the Microsoft DirectX collection of APIs. Other DirectX APIs include Direct3D, Direct2D, DirectWrite, DirectDraw, DirectMusic, DirectPlay, and DirectSound.

DirectCompute will initially be released with the DirectX 11 API but runs on both DirectX 10 and DirectX 11 graphics processing units (GPUs).^[1]

GPUs bring a massively parallel approach to PC tasks with hundreds of processing cores in a single chip. An example to illustrate this: You have a book and a software program designed to count the number of times a certain word is used in that book. Run that program on a CPU (a serial/sequential processor) and it would start on page 1, read the entire book word-by-word, page-by-page until it finished and eventually give you an answer. Give that same problem to a GPU (a parallel processor) that supports DirectCompute and it would tear that book into thousands of pieces, and read through all of them simultaneously. See UC Berkeley’s David Patterson (scientist)’s presentation.

DirectCompute defines several versions of Compute Shader capabilities to ensure that applications can take advantage of GPU Computing on hundreds of millions of consumer systems already in the market today, and also have the flexibility to adopt new features exposed in DirectX 11 capable GPUs when they are available. DirectCompute shader versions 4.0, 4.1, and 5.0 correspond to DirectX 10.0, 10.1, and 11 respectively. Developers can start using Compute Shader 4.x kernels in their applications today, and add Compute Shader 5.x capabilities as the installed base of DirectX 11 GPUs becomes a significant portion of target market (typically millions of units).^[2]