X-bit labs

Valve Software Expresses Strong Commitment to Multi-Core Computing.

Category: CPU

by Anton Shilov

[ 10/15/2007 | 10:20 PM ]

Gabe Newell, the chief of Valve Software game developer, said in an interview that he still considers Ageia PhysX and Sony PlayStation 3 as two inadequate products. Besides, the head of software maker that creates popular Half-Life 2 and Counter Strike titles reiterated commitment to multi-core central processing units as well as general purpose GPU computing, such as physics or artificial intelligence.

“[With the introduction of multi-core CPUs] performance and scaling has stopped being a hardware problem and instead it’s been turned into a software problem. That’s bad news for us, software guys – but for hardware it’s good news, because it shifts the value proposition towards software developers. What it also means is clock rates will stay pretty much the same, but the number of execution units you have is going to explode. The good news is that we’re going to spend an era of growing linearly for a while, so transistor budgets will translate directly to improvements,” said Mr. Newell in an interview with Next Generation web-site.

Currently central processing units (CPUs) have up to four processing engines, whereas graphics processing units (GPUs) can feature tens or even hundreds of execution engines, meaning that GPUs are better prepared to the new programming paradigm, which involves tens and hundreds of threads. Still, considering that Intel Corp. can is working on high-performance microprocessors with eight and more engines, application-specific accelerators and other ways to improve their capabilities, Valve still does not make any final judgments whether general purpose computing on GPUs or CPUs will take the lead eventually.

“We understand we have to make these investments in multi-core. We have to worry about not just two cores, but 64 threads, 512 threads – how are we going to reorganize it? [The] more we look at it, the more excited we get. This current era is one of heterogeneous computing: you’ve got this one big chunk of code doing physics and AI, character animation and facial systems talking through this strange interface called DirectX to another chunk of your code which you write to run on GPUs. That’s just going to go away. And either [GPU] or [CPU] is going to win the battle for whose array of cores is taken up,” Mr. Newell said.

Despite of the fact that both Microsoft Xbox 360 and Sony PlayStation 3 essentially use multi-core microprocessors, the head of Valve does not criticize Microsoft’s game console, saying that investments into parallelizing the code for three cores will be useful for personal computers as well. By contrast, Mr. Newell claims for some reason that investments into learning how to develop applications for Sony PS3’s Cell are useless.

“I think [PS3 is] a waste of everybody’s time. Investing in the Cell, investing in the SPE gives you no long-term benefits. There’s nothing there that you’re going to apply to anything else. You’re not going to gain anything except a hatred of the architecture they’ve created. I don’t think they’re going to make money off their box. I don’t think it’s a good solution,” said Mr. Newell.

Finally, Mr. Newell said he did not like the idea of application-specific physics accelerator.

“I think that’s a horrible idea. At the same time that the distinction between the GPU and CPU is going away, the PPU guys want to come in and define a new set of abstractions, where we have memory and data that’s really far away from the CPU and CPU... How do I tell when something breaks, or gets pushed by a monster? All these decisions I have on my CPU have to sit around until they are resolved on the PPU and GPU, and you end up with a physics decelerator. This is the reason you want a homogenous architecture,” he said.