Intel's Larrabee Architecture Disclosure: A Calculated First Move
by Anand Lal Shimpi & Derek Wilson on August 4, 2008 12:00 AM EST- Posted in
- GPUs
A Tribute to Michael Abrash: The ISA
Some people idolize athletes. Others gravitate towards entertainers. While Derek is a hockey fan and a musician who loves watching movies, his real passion lead him in a different direction. And he's also going to devolve into first person singular for a minute to tell you a little more about that.
At the time I was a high school student who needed a good project outside the curriculum to teach to our C++ programming class (this was another one of the excellent projects Jo Adams set her students upon). My good friend Tom Macleod and I had just learned enough calculus and advanced geometry to be dangerous: we decided to write a 3D graphics engine in order to learn and teach graphics programming to the class.
To support this endeavor, I spent a bit of cash (well, my parent's cash anyway) on some graphics and game programming books for the occasion, and the one that really stood out (the one that set the course of my life) was Michael Abrash's Graphics Programming Black Book Special Edition. This giant tome contained quite a bit of collected wisdom regarding the art and science of code optimization and graphics programming as well as some great details about the development of Quake.
Not only was his book an incredible source of information and inspiration for me personally, but if there was ever an x86 assembly guru and graphics programming god that could help take the design of an instruction set architecture for Larrabee to a whole other dimension, it is Michael Abrash. And our information indicates that he has done just that.
This isn't to say that others on the Larrabee team don't deserve a spotlight; it's just exciting to see the guy who got me hooked on computer graphics programming (which lead to my interest in hardware) show up on such an impressive graphics hardware design team.
For those who haven't idolized Abrash, his Wikipedia entry helps explain his luminary status in the game industry:
"Michael Abrash is a highly regarded technical writer, and one of the top optimization and 80x86 assembly language programmers, a reputation cemented by his 1990 book Zen of Assembly Language Volume 1: Knowledge. Before getting into technical writing, Abrash was a game programmer, having written his first commercial game in 1982. After working at Microsoft on graphics and assembly code for Windows NT 3.1, he returned to the game industry in the mid-1990s to work on Quake for id Software. Some of the technology behind Quake is documented in Abrash's Graphics Programming Black Book. After Quake was released, Abrash returned to Microsoft to work on natural language research, then moved to the Xbox team, until 2001. In 2002, Abrash went to work for RAD Game Tools, where he co-wrote the advanced Pixomatic software renderer, which emulates the functionality of a DirectX 7-level graphics card and is used as the software renderer in such games as Unreal Tournament 2004."
Intel brought Abrash on as a consultant to help define the Larrabee instruction set. For the longest time, extensions to x86 (e.g. SSE4) were done by Intel engineers at the request of the software community. With every iteration of SSE the game industry was always happier but never truly satisfied with the extensions to x86 that Intel introduced. When Intel set out to define the extensions to x86 that would be used in Larrabee, it sought out visionaries within the game industry to help define that spec rather than creating hardware and defining the ISA internally. One thing we've consistently heard from game developers about Larrabee is that the ISA makes more sense than any other approach they have seen from ATI or NVIDIA. Larrabee's ISA was designed in part by the game industry, for that very industry.
Interestingly enough, while reluctant to go into details about the Larrabee ISA itself, Intel did tell us that fewer than 5% of the instructions are graphics specific. What they found is that creating overly specialized instructions doesn't always do that much good as they can be hard for compilers to use effectively and difficult to hand optimize with as well. Rather, having a good selection of generally applicable and powerful instructions is a better way to go.
One of the advantages of developing the compiler in parallel with the ISA itself is that they can easily test and adapt both as needed to understand how best to balance the ISA. As the vast majority of developers will rely on compilers to generate highly performant code, making sure the ISA is a good fit for compilers is essential. At the same time, because of the renewed interest in software graphics engines Larrabee is stirring up in the Old Guard of real-time 3D computer graphics, having icons like Michael Abrash on the team will help make sure that the ISA is not only compiler friendly but will also be attractive to those who wish to achieve Zen through assembly optimization.
Which brings us to an interesting point.
101 Comments
View All Comments
phaxmohdem - Monday, August 4, 2008 - link
Can your mom play Crysis? *burn*JonnyDough - Monday, August 4, 2008 - link
I suppose she could but I don't think she would want to. Why do you care anyway? Have some sort of weird fetish with moms playing video games or are you just looking for another woman to relate to?Ooooh, burn!
Griswold - Monday, August 4, 2008 - link
He is looking for the one playing his mom, I think.bigboxes - Monday, August 4, 2008 - link
Yup. He worded it incorrectly. It should have read, "but can it play your mom?" :pTilmitt - Monday, August 4, 2008 - link
I'm really disappointed that Intel isn't building a regular GPU. I doubt that bolting a load of unoptimised x86 cores together is going to be able to perform anywhere near as well as a GPU built from the ground up to accelerate graphics, given equal die sizes.JKflipflop98 - Monday, August 4, 2008 - link
WTF? Did you read the article?Zoomer - Sunday, August 10, 2008 - link
He had a point. More programmable == more transistors. Can't escape from that fact.Given equal number of transistors, running the same program, a more programmable solution will always be crushed by fixed function processors.
JonnyDough - Monday, August 4, 2008 - link
I was wondering that too. This is obviously a push towards a smaller Centrino type package. Imagine a powerful CPU that can push graphics too. At some point this will save a lot of battery juice in a notebook computer, along with space. It may not be able to play games, but I'm pretty sure it will make for some great basic laptops someday that can run video. Not all college kids and overseas marines want to play video games. Some just want to watch clips of their family back home.rudolphna - Monday, August 4, 2008 - link
as interesting and cool as this sounds, this is even more bad news for AMD, who was finally making up for lost ground. granted, its still probably 2 years away, and hopefully AMD will be back to its old self (Athlon64 era) They are finally getting products that can actually compete. Another challenger, especially from its biggest rival-Intel- cannot be good for them.bigboxes - Monday, August 4, 2008 - link
What are you talking about? It's been nothing but good news for AMD lately. Sure, let Intel sink a lot of $$ into graphics. Sounds like a win for AMD (in a roundabout way). It's like AMD investing into a graphics maker (ATI) instead of concentrating on what makes them great. Most of the Intel supporters were all over AMD for making that decision. Turn this around and watch Intel invest heavily into graphics and it's a grand slam. I guess it's all about perspective. :)