Running Linux on a GPU is not a pipe-dream

TG Daily: If your vision comes true, it looks like graphics will take the best from the CPU and the GPU, with graphics hardware continuing its evolution from a fixed function pipeline into what are basically arrays of mini-processors that support almost the same data formats as floating point units on the CPU today.

Sweeney: It is hard to say at what point we are going to see graphics hardware being able to understand C++ code. But data will be processed right on the GPU. Then, you are going to get the GPU's computational functionality to a point where you can - not that this is useful, but it will be a very important experiment - recompile the kernel for a GPU and actually run the Linux kernel off the GPU - running entirely by itself. Then, the boundary between the CPU and the GPU will become just a matter of performance trade-offs.

TG Daily: General purpose GPUs competing with CPUs? Do you already have any idea who might win this battle?

Sweeney: Hard to say at this time. Both can run any kind of code, GPUs are just much better optimized for highly parallel vector computing. CPUs are better for authorized out-of-order, branching, and operating system type of things. Once they both have a complete feature-set, things will get very interesting there. We could see the CPU pushing GPUs out of the market entirely, if the integration of highly parallel computing influences future designs. Or, we could see GPU vendors start pushing actual CPUs out of the market: Windows or any other operating system could run directly on a GPU. There are lots of possibilities.


TG Daily: In some way, this is already happening in the handheld world. STMicro recently launched a chip that integrates the ATI z460 GPU a.k.a.  
mini-Xenos [a trimmed-down version of the Xbox 360 GPU -ed]. Nvidia launched the APX2500, a system-on-a-chip product that uses an ARM11 core for CPU-type computing and an ULP GeForce for the rest of the system. Intel is talking about such SoCs for the consumer electronics segment. Will we see something similar on the desktop?

Sweeney: It is unclear what these products actually are. As they become actual silicon, we will be able to see how far the miniaturization can go.


TG Daily: There are signs that a whole new market segment might reveal itself, enabling 3D performance with CPU-type computing on handheld-type devices, which so far provided pathetic a 3D GUI experience for users.

Sweeney: Well, if we look at the iPhone, we can see that these low-power devices can actually be very important part of our lives. Now you can really browse the Web on a handheld - I mean you can actually browse the web in a decent fashion. Look at my Blackberry [8700]. There is a crappy little web browser thrown in to provide the simple functionality and it just sucks. It is a horrible web experience. Apple’s version is really good, it is usable. The video player and the YouTube integration are excellent. I definitely see those devices becoming a much more important part of our lives. For that reason, we need more and more compute power inside the same size package.

TG Daily: But realistically, will it ever be possible to run a high-end game on a handheld platform?

Sweeney: The way people go online and do things replaced a lot of things we used to do on our PCs, but not everything, of course. You don't use your handheld and write a document in word processing software. You don't spend hours playing a game on a handheld because the battery won't last. And these are tiny screens. Why would you play on a handheld, if you can play on large screens and enjoy the full experience of a game?

These [small] devices are important and I feel they will grow over time, as processing capabilities increase. I believe that the next generation of mobile gaming will be quite impressive. I think we're only few years away from really good user experience [in all segments]. If you look at the PlayStation Portable or Nintendo’s handhelds, they are so low-end and so low-performance that they are just not interesting to mainstream game developers. But with another generation or two, they will have enough power to run a scaled down version of a high-end game console or PC game. Reduce the level of detail, lower the resolution and you will get the same game running on these devices.


TG Daily: Then, it would not be a far-fetched call to see games based on next-gen engines such as Unreal Engine 4, even 4.5 or 5 or something like that, running on a device that fits in your pocket?

Sweeney: That is the great thing about this scalable factor. On a 320x200 pixel screen, you have 30 times less pixels than on the highest-end PC monitor that is currently available. When you look at the performance figures, the actual scale is within reach. It should be possible to create a compelling next-gen experience on consoles, PC and handhelds.



This concludes the second part of our interview. We will publish the final segment tomorrow, which will focus on Epic’s plans for the Unreal Engine 4.0 .

Read the first part of the interview here: Tim Sweeney, Part 1: "PCs are good for anything, just not games"

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