I had a pretty bad experience last year when using an ATI for a demo involving OpenCL. I'd done the majority of the programming on an nVidia 9600 and had great performance, only to find framerates of 3fps on the ATI 4870.
When looking at all of the programming in question, when using a perlin warp kernel to deform a 256x256 grid, I was getting 60fps. The second I introduced a texture, everything tanked. If a CL kernel had to analyze image and derive values, everything seemed to be running CPU, and fairly badly. I do not remember if I ran the CL Device Info patch or not (I don't think I did!), but I do remember that I also ran a CL example Xcode project that features some environment mapping and a mesh being deformed with CL, with some different GLSL shaders. It ran fine, but the texturing was via GLSL, and the warp was a similar perlin kernel. The lesson I learned out of it was to use OpenCL only when I'm certain of the device I'll be targeting, and at that, to still use it very cautiously and expect that breakage may occur with software updates. This makes it very unappealing, despite potential performance benefits and some flexibility that it offers. Even in a scenario where GPU's are supported, what is or isn't acceptable inside of the kernel has shifted without documentation or release note. It makes it hard to sort driver problems from actual QC bugs, from CL framework bugs, or for that matter, Mesh Creator/Renderer bugs. On Sun, Jul 24, 2011 at 12:01 AM, Glen Speckert <speck...@specktech.com>wrote: > Under Snow Leopard, when I tried any of the following cards in a Mac Pro > Westmere, the only OpenCL devices reported by QC was the Intel CPU (although > there were 12 CPUs reported, hence the hyper threading was working ). > > The cards I tried were: > ATI 5870 > ATI 5770 > Nvidia Quadro 4000 for Mac > ( which did run CUDA on the Mac, for certain MATLAB licenses ) > > There was a discussion that OpenCL support, and QC use of OpenCL were not > the same, but to be honest, this seems like splitting hairs to me. I was > disappointed with Apple's Hype for OpenCL support, relative to the > engineering reality of trying to use OpenCL in Quartz Composer. > > What does it mean for a card to support OpenCL if when using the OpenCL > development tool, the card is not part of the implementation? > > -- Glen > > On Jul 23, 2011, at 8:40 PM, Alastair Leith wrote: > > A GPU card's support for OpenCL in OS X applications is not same thing as > support for OpenCL patches inside Quartz Composer environment if I recall > correctly. Somebody please fill in gaps/correct if I'm wrong. > > > > On 24/07/2011, at 6:36 AM, Paul Harrison wrote: > > I have constructed a simple .qtz composition using OpenCL Context Info > patch which reports that my iMac has an OpenCl > Device Count of 1, > Device Type of CL_DEVICE_CPU, and > Name of "Intel(R) Core(TM) i& CPU 860 @ 2.80GHz. > > But, the iMac'a system info reports under Graphics/Displays that it also > sports an > ATI Radeon HD 4850: > Chipset Model: ATI Radeon HD 4850 > Type: GPU > Bus: PCIe > PCIe Lane Width: x16 > VRAM (Total): 512 MB > Vendor: ATI (0x1002) > Device ID: 0x944a > Revision ID: 0x0000 > ROM Revision: 113-B9110C-425 > EFI Driver Version: 01.00.383 > > And the Apple website http://www.apple.com/macosx/specs.html says: > > "OpenCL > requires one of the following graphics cards or graphics processors: > > NVIDIA GeForce 320M, GeForce GT 330M, GeForce 9400M, GeForce 9600M GT, > GeForce 8600M GT, GeForce GT 120, GeForce GT 130, GeForce GTX 285, GeForce > 8800 GT, GeForce 8800 GS, Quadro FX 4800, Quadro FX5600 > ATI Radeon HD 4670, ATI Radeon HD 4850, Radeon HD 4870, ATI Radeon HD 5670, > ATI Radeon HD 5750, ATI Radeon HD 5770, ATI Radeon HD 5870 > AMD Radeon HD 6750M, AMD Radeon HD 6770M, AMD Radeon HD 6970M" > > Seeing as how the official apple list of OpenCL supported graphics > processors lists ATI Radeon HD 4850 and my machine reports having an ATI > Radeon HD 4850 installed, why does Quartz Composer (version 4.0 103.1) not > report it in the OpenCL Context Info? > > The machine is running Mac OS X Version 10.6.8. > > Paul > > > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Quartzcomposer-dev mailing list (Quartzcomposer-dev@lists.apple.com) > Help/Unsubscribe/Update your Subscription: > > http://lists.apple.com/mailman/options/quartzcomposer-dev/qc.student.au%40gmail.com > > This email sent to qc.student...@gmail.com > > > *The machine does not isolate man from the great problems of nature but > plunges him more deeply into them.** > **Antoine de > Saint-Exupery*<http://www.brainyquote.com/quotes/quotes/a/antoinedes131176.html> > * * > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Quartzcomposer-dev mailing list (Quartzcomposer-dev@lists.apple.com) > Help/Unsubscribe/Update your Subscription: > > http://lists.apple.com/mailman/options/quartzcomposer-dev/speckert%40specktech.com > > This email sent to speck...@specktech.com > > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Quartzcomposer-dev mailing list (Quartzcomposer-dev@lists.apple.com) > Help/Unsubscribe/Update your Subscription: > > http://lists.apple.com/mailman/options/quartzcomposer-dev/gtoledo3%40gmail.com > > This email sent to gtole...@gmail.com > > -- George Toledo gtole...@gmail.com www.georgetoledo.com
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