[NocturnDragon]

As Jen-Hsun Huang pre-announced the other day:

"Apple knows a lot about CUDA," Huang said, implying the company might be ready to formally embrace Nvidia's technology to make it easier to exploit graphics chips inside Macs. Apple's implementation "won't be called CUDA, but it will be called something else,"

Apple yesterday announced it's own GPGPU solution called OpenCL. (not to be confused with OpenCL the cryptography library now called Botan)
So far there are only a few details available:

• It will be released on apple platforms a year from now with OS X 10.6 Snow Leopard.
• Apple proposed it as an open standard. (through Khronos?)
• it will have a C based syntax (but what language today doesn't?)

On the apple site you can read:
http://www.apple.com/macosx/snowleopard/

OpenCL
Another powerful Snow Leopard technology, OpenCL (Open Compute Library), makes it possible for developers to efficiently tap the vast gigaflops of computing power currently locked up in the graphics processing unit (GPU). With GPUs approaching processing speeds of a trillion operations per second, they’re capable of considerably more than just drawing pictures. OpenCL takes that power and redirects it for general-purpose computing.

Press Release:
http://www.apple.com/pr/library/2008...owleopard.html

Is there any other information about it?

[Rufus]

Steve's reality distortion field, or is there something that is missing?

Originally Posted by http://bits.blogs.nytimes.com/2008/06/10/apple-in-parallel-turning-the-pc-world-upside-down/

Mr. Jobs described a new processing standard that Apple is proposing called OpenCL (Open Computing Language) which is intended to refocus graphics processors on standard computing functions.

“Basically it lets you use graphics processors to do computation,” he said. “It’s way beyond what Nvidia or anyone else has, and it’s really simple.”

[patsu]

OpenCL is based on LLVM and Clang.

In fact, Grand Central Dispatch is also very interesting.

[NocturnDragon]

Originally Posted by patsu

OpenCL is based on LLVM and Clang.

In fact, Grand Central Dispatch is also very interesting.

Yeah I was guessing LLVM would have been involved...

Do you have any link about that tho?

[patsu]

I think the Wiki entry for OpenCL says as much.

I am trying to find more info about Grand Central Dispatch from Apple's developer site (Though it is not GPGPU per se). Like the Cell processor, GCD reminds me of supercomputing concept(s) from more than a decade ago (From the Cray, Thinking Machine, PVM supercomputing era).

[jimmyjames123]

I thought this was very interesting news, especially the tidbit by Steve Jobs that this was "way beyond" what NVIDIA and others have. Logically I don't think that makes sense (since CUDA has already proven it's worth in various real-world scenarios), unless he meant that it is way beyond in the sense that it is not specific to only one set or type of graphics cards.

Does anyone know what are the real differences between CUDA and OpenCL? They sure sound similar in function on the surface.

One thing I don't quite follow is that, on Wikipedia CUDA page, it says that OpenCL is similar technology to CUDA and that Apple has a partnership with NVIDIA and others in promoting this standard.

So maybe NVIDIA realizes that CUDA has to become universally used for it to be successful, and is therefore supporting OpenCL as an alternative to Intel's upcoming GPGPU software platform?

[patsu]

It probably means that nVidia's CUDA implementation can be folded under LLVM's compiler framework on Mac OS X. LLVM (and hence, OpenCL) can support other language run-time.

[NocturnDragon]

http://www.amd.com/us-en/Corporate/VirtualPressRoom/0,,51_104_543~126593,00.html

In keeping with its open systems philosophy, AMD has also joined the Khronos Compute Working Group. This working group’s goals include developing industry standards for data parallel programming and working with proposed specifications like OpenCL. The OpenCL specification can help provide developers with an easy path to development across multiple platforms.


“An open industry standard programming specification will help drive broad-based support for stream computing technology in mainstream applications,” said Rick Bergman, senior vice president and general manager, Graphics Product Group, AMD. “We believe that OpenCL is a step in the right direction and we fully support this effort. AMD intends to ensure that the AMD Stream SDK rapidly evolves to comply with open industry standards as they emerge.”

[Simon F]

Khronos Press Release on the related topic

[NocturnDragon]

Originally Posted by Simon F

Khronos Press Release on the related topic

Too bad there is not much information in it.

“Significantly, this initiative is aimed at both desktop and embedded devices – the day when you will be able to hold a supercomputer in the palm of your hand is perhaps not so far away.”

Future embedded devices, or current ones (OpenGL ES 2.0 generation)?

[PeterT]

Well, it has seemed obvious for a while now that the main roadblock to wide (or even wider) GPGPU adoption is the lack of a platform and vendor agnostic, open, standardized programming interface. If this OpenCL initiative is actually serious and capable of producing something usable in a reasonable timeframe it will become very significant. I for one am quite excited.

[NocturnDragon]

Originally Posted by PeterT

Well, it has seemed obvious for a while now that the main roadblock to wide (or even wider) GPGPU adoption is the lack of a platform and vendor agnostic, open, standardized programming interface. If this OpenCL initiative is actually serious and capable of producing something usable in a reasonable timeframe it will become very significant. I for one am quite excited.

I sure share your feelings, but I am also a bit scared of the timeframe, as the OpenGL 3 fiasco showed, khronos can take it's time to standardize things.

Hopefully the push Apple is giving will be enough to overcome that.

[PeterT]

Originally Posted by NocturnDragon

I sure share your feelings, but I am also a bit scared of the timeframe, as the OpenGL 3 fiasco showed, khronos can take it's time to standardize things.

Thinking of the OpenGL 3 "process" is what made me put the qualifier "in a reasonable timeframe" there

[NocturnDragon]

Originally Posted by PeterT

Thinking of the OpenGL 3 "process" is what made me put the qualifier "in a reasonable timeframe" there

Well my impression was that the 10.6 version they gave to WWDC attendees already has an early implementation... But I might be way wrong.

[Karoshi]

Dont remember if dx11 had a compute shader planed. If it didnt, we can look forward to a rushed one. No way MS will let anything multiplatform go ahead unchallenged by a propietary alternative.

[nAo]

DX11 compute shaders are similar to CUDA..

[darkblu]

so when you try to do a software rasterizer on opencl will the universe implode into a violent singularity?

[iwod]

I think they should focus on getting OpenGL3 or even OpenGL 3.1 done first. Then OpenCL.
And may be when they have time to fix the OpenAL problems with a rewrite.

[randomhack]

Maybe they are including OpenCL or something related in OpenGL 3 and maybe thats why its taking so much time?

[NocturnDragon]

Originally Posted by iwod

I think they should focus on getting OpenGL3 or even OpenGL 3.1 done first. Then OpenCL.
And may be when they have time to fix the OpenAL problems with a rewrite.

They who?
I don't think it's the OpenGL and OpenCL groups are the same.
And btw OpenAL is not a Khronos standard.

[iwod]

Just wondering what are the chances of using OpenCL on Intel X4500?

[randomhack]

I have to wonder whether Intel is supporting OpenCL on Larrabee. If claims of Intel that Larrabee is much more programmable than current cores is correct, they shouldnt have much of a problem in supporting any standard.
I am also wondering if Apple will be using Larrabee? Are Snow Leopard and Larrabee scheduled in the same time frame?

[trinibwoy]

Originally Posted by nAo

DX11 compute shaders are similar to CUDA..

In what respect? Do the structures map well to the Grid -> Block -> Warp -> Thread CUDA hierarchy?

[TimothyFarrar]

Originally Posted by trinibwoy

In what respect? Do the structures map well to the Grid -> Block -> Warp -> Thread CUDA hierarchy?

Or a better question is how exactly they are making the functionality portable without hindering performance. CUDA performance is all about fetching aligned full memory bus granularity blocks into "shared memory" and then allowing the SIMD units to do swizzled fetches from that shared pool. Kind of hard to see this porting well to AMD chips..

[nAo]

Originally Posted by trinibwoy

In what respect? Do the structures map well to the Grid -> Block -> Warp -> Thread CUDA hierarchy?

That's an abstraction that would hardly work on a wide range or architectures.
Compute shaders should be an opportunity to refine CUDA and get it a bit more right (who cares about number of warps/blocks/grids/wavefront/whatever..)