GPU Computing

Vol. 6 No. 2 – March/April 2008

GPU Computing

Latency and Livelocks:
Sometimes data just doesn’t travel as fast as it should.

Dear KV: My company has a very large database with all of our customer information. The database is replicated to several locations around the world to improve performance locally, so that when customers in Asia want to look at their data, they don’t have to wait for it to come from the United States, where my company is based...

by George Neville-Neil

A Conversation with Kurt Akeley and Pat Hanrahan:
Graphics veterans debate the evolution of the GPU.

Interviewing either Kurt Akeley or Pat Hanrahan for this month’s special report on GPUs would have been a great opportunity, so needless to say we were delighted when both of these graphics-programming veterans agreed to participate. Akeley was part of the founding Silicon Graphics team in 1982 and worked there for almost 20 years, during which he led the development of several high-end graphics systems, including GTX, VGX, and RealityEngine. He’s also known for his pioneering work on OpenGL, the industry-standard programming interface for high-performance graphics hardware. Akeley is now a principal researcher at Microsoft Research Silicon Valley, where he works on cutting-edge projects in graphics system architecture, high-performance computing, and display design.

Data-Parallel Computing:
Data parallelism is a key concept in leveraging the power of today’s manycore GPUs.

Users always care about performance. Although often it’s just a matter of making sure the software is doing only what it should, there are many cases where it is vital to get down to the metal and leverage the fundamental characteristics of the processor.

by Chas. Boyd

Future Graphics Architectures:
GPUs continue to evolve rapidly, but toward what?

Graphics architectures are in the midst of a major transition. In the past, these were specialized architectures designed to support a single rendering algorithm: the standard Z buffer. Realtime 3D graphics has now advanced to the point where the Z-buffer algorithm has serious shortcomings for generating the next generation of higher-quality visual effects demanded by games and other interactive 3D applications. There is also a desire to use the high computational capability of graphics architectures to support collision detection, approximate physics simulations, scene management, and simple artificial intelligence. In response to these forces, graphics architectures are evolving toward a general-purpose parallel-programming model that will support a variety of image-synthesis algorithms, as well as nongraphics tasks.

by William Mark

GPUs: A Closer Look:
As the line between GPUs and CPUs begins to blur, it’s important to understand what makes GPUs tick.

A gamer wanders through a virtual world rendered in near- cinematic detail. Seconds later, the screen fills with a 3D explosion, the result of unseen enemies hiding in physically accurate shadows. Disappointed, the user exits the game and returns to a computer desktop that exhibits the stylish 3D look-and-feel of a modern window manager. Both of these visual experiences require hundreds of gigaflops of computing performance, a demand met by the GPU (graphics processing unit) present in every consumer PC.

by Kayvon Fatahalian, Mike Houston

Scalable Parallel Programming with CUDA:
Is CUDA the parallel programming model that application developers have been waiting for?

The advent of multicore CPUs and manycore GPUs means that mainstream processor chips are now parallel systems. Furthermore, their parallelism continues to scale with Moore’s law. The challenge is to develop mainstream application software that transparently scales its parallelism to leverage the increasing number of processor cores, much as 3D graphics applications transparently scale their parallelism to manycore GPUs with widely varying numbers of cores.

by John Nickolls, Ian Buck, Michael Garland, Kevin Skadron

Solomon’s Sword Beats Occam’s Razor:
Choosing your best hypothesis

I’ve told you a googol times or more: Don’t exaggerate! And, less often, I’ve ever-so-gently urged you not to understate. Why is my advice ignored? Why can’t you get IT... just right, balanced beyond dispute? Lez Joosts Mildews, as my mam was fond of sayin, boxing both my ears with equal devotion. Follow the Middle Way as Tao did in his Middle Kingdom. Or "straight down the middle," as golfer Bing Crosby used to croon. His other golf song was "The Wearing of the Green," but such digressions run counter to my straight, plow-on-ahead advice. I’ve just smoked a cigarette branded Cleopatra, but that’s none of your beeswax neither, and strictly between me and my Egyptian placements sponsor.

by Stan Kelly-Bootle