Hacker News Reader

Comment by phren0logy | Hacker News Reader

I'm not sure if you are joking (given that it is a lisp, which is notoriously not mainstream), but my limited experience with GPU programming with the existing tools has been pretty painful. I, for one, welcome this development.

View on HN

The lisp part isn't necessary (or necessarily helpful), but it's certainly an improvement on embedding C-as-a-string in more C.

...though I am concerned that abstracting this stuff too much makes it less obvious how to optimize for the GPU. This may be a language for people that already have a solid grasp on GPU programming.

>> embedding C-as-a-string in more C

Um. OpenCL/Cuda look absolutely nothing like that.

>> embedding C-as-a-string in more C >Um. OpenCL/Cuda look absolutely nothing like that.

Absolutely right. You can also include an external C file from C++ [1]; that makes it so much prettier.

[1] http://developer.amd.com/tools-and-sdks/heterogeneous-comput...

Yes, anything to make it easier to get started. I've tried before, but got lost in figuring out which SDK to download. Too bad this toolkit doesn't help in that process.

Happily, writing this answer I discovered that OS X 10.7+ ships with OpenCL already! Can't believe I missed that last time.

For anyone else wanting to try it, the first example is pretty straight forward:

https://developer.apple.com/library/mac/#documentation/Perfo...

(You'll also want the code examples at https://developer.apple.com/library/mac/#documentation/Perfo... )

Are GLSL and OpenCL equally capable?

Not exactly sure what you're asking, but GLSL and OpenCL are for two different domains: GLSL for graphics and OpenCL for calculations that are not intended to show up as graphics.

They both run on the same hardware, but I don't have enough (or really any) experience with OpenCL to say if it feels more or less powerful than GLSL.

Edit: It turns out that I have no OpenCL hardware support (mid 2011 MBA), so I guess the hardware isn't necessarily completely similar (i.e. it can support GLSL and not OpenCL)

This isn't entirely true. As of OpenGL 4.3 (latest spec), OpenGL adds compute shaders as well. Their primary usage is to make interopt with the graphics pipeline less painful than it would be with OpenCL, but in theory you could use OpenGL (or DX11 on Windows) compute shaders for non-graphics tasks, and they'd have roughly the same capabilities as CUDA or OpenCL.

OpenCL is used to JIT OpenGL calls based on the hardware. Its magic.

The OpenCL implementation provided by Apple is less than ideal. It lacks a number of optimizations that are provided by, for example, AMD's OpenCL driver packages for Linux and Windows.

That, coupled with the wretched GPU options available on the Mac Pro, make the current stack not really cost effective. (I think a 5770 is still $250.)

However, it is better than CPU-only.

I've found slaving a cheap Linux box with expensive GPUs to be a much more gratifying experience.

I've done most of my development on a Mac, but I keep finding many bugs in Apple's OpenCL implementation. Intel's seems to follow the standard most closely, which is useful for keeping me honest.

Not joking.

Reply on news.ycombinator.com