Need to install opencl for CPU and GPU platforms?
I have a system with an NVidia graphics card and I'm looking at using openCL to replace openMP for some small on CPU tasks (thanks to VS2010 making openMP useless)
Since I have NVidia's opencl SDK installed clGetPlatformIDs() only returns a single platform (NVidia's) and so only a single device (the GPU).
Do I need to also install Intel's openCL sdk to get access to the CPU platform?
Shouldn't the CPU platform always be available - I mean, how do you NOT have a cpu?
How do you manage to build against two openCL SDKs simultaneously?
You need to have a SDK which provides interface to CPU. nVidia does not, AMD and Intel's SDKs do; in my case the one from Intel is significantly (something like 10x) faster, which might due to bad programming on my part however.
You don't need the SDK for programs to run, just the runtime. In Linux, each vendor installs a file in /etc/OpenCL/vendors/*.icd , which contains path of the runtime library to use. That is scanned by the OpenCL runtime you link to (libOpenCL.so), which then calls each of the vendor's libs when querying for devices on that particular platform.
In Linux, the GPU drivers install OpenCL runtime automatically, the Intel runtime is likely to be downloadable separately from the SDK, but is part of the SDK as well, of course.
Today i finally got around to trying to start doing openCl development and wow... it is not straight forward at all.
There's an AMD sdk, there's an intel sdk, there's an nvidia sdk, each with their own properties (CPU only vs GPU only vs specific video card support only perhaps?)
There may be valid technical reasons for it having to be this way but i really wish there was just one sdk, and that when programming perhaps you could specify GPU / CPU tasks, or that maybe it would use whatever resources made most sense / preformed best or SOMETHING.
Time to dive in though I guess... trying to decide though if i go CPU or GPU. I have a pretty new 4000$ alienware laptop with SLI video cards, but then also an 8 core cpu so yeah... guess ill have to try a couple sdk's and see which preforms best for my needs?
Not sure what end users of my applications would do though... it doesnt seem like they can flip a switch to make it run on cpu or gpu instead.
The OpenCL landscape really needs some help...
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