Error Cl_Device_Not_Available When Calling Clcreatecontext (Intel Core2Duo, Intel Ocl Sdk 3.0 Beta)

Error CL_DEVICE_NOT_AVAILABLE when calling clCreateContext (Intel Core2Duo, Intel OCL SDK 3.0 beta)

Intel OpenCL CPU needs at least SSE 4.1. The Core 2 Duo only goes up to SSSE3.

http://software.intel.com/en-us/articles/opencl-sdk-frequently-asked-questions#14

Edit: some version of the Core 2 Duo support SSE 4.1
Here is the list of supported processors for the Intel OpenCL drivers
http://software.intel.com/en-us/articles/opencl-release-notes#2

Some versions of Core 2 are not supported. " All other versions of Intel® Core™ 2 processors are not supported"

You can use, for example, CPU-Z to find out what version of SSE you CPU supports.

Install the AMD OpenCL CPU driver. It only needs SSE2. On windows I installed the Radeon GPU drivers even though I did not have a AMD GPU. It still installed the AMD OpenCL CPU drivers and it did not conflict with the Nvidia drivers. I don't know on Linux. But now I can use Intel CPU, AMD CPU, and Nvidia GPU OpenCL drivers.

CL_DEVICE_NOT_AVAILABLE using Intel Core 2 Duo E8500 CPU

"CL_DEVICE_NOT_AVAILABLE" has nothing to do with the SDK. It's due to the OpenCL device driver which is part of the video card device driver.

It's common to confuse the SDK and the OpenCL device driver. You develop the host code with the SDK but the kernel is compiled and run through the device driver. I often develop with the Intel SDK but I run my kernels on the CPU using the Intel video driver or the AMD Radeon drivers and on the GPU using the Nvidia video drivers (GTX590). I have all three video drivers installed in Windows. You don't have to have an AMD video card to instal the Radeon drivers.

So in your case you can use the AMD drivers to run your kernel on the CPU. They are much less restrictive than Intel's.

On windows I get faster results running my Kernel on my Sandy Bridge CPU using the Intel OpenCL drivers than AMD. However, on Linux the AMD driver runs my kernel faster on my Intel CPU than the Intel driver does.

Device says it is available, but can't create context in OpenCL

So a possible explanation could be that it's due to the Intel SDK as explained in that post. To quote the main idea:

Intel OpenCL CPU needs at least SSE 4.1. The Core 2 Duo only goes up
to SSSE3.

The solution given was:

Install the AMD OpenCL CPU driver. It only needs SSE2.

Install OpenCL on Ubuntu 14.04 and Nvidia

Since you want to use your nVidia GPU, you will need to install the nVida OpenCL runtime, which is part of the GPU driver. You should not need the Intel OpenCL SDK. A simple

sudo apt-get install nvidia-opencl-dev

should install everything you need. Alternatively, download nVidia CUDA 7.5 from https://developer.nvidia.com/cuda-downloads. This also includes OpenCL.

How to install libOpenCL.so on ubuntu

Looks like all I had to do is

sudo apt update

sudo apt install ocl-icd-opencl-dev

Thanks to Nick Weindberg
https://askubuntu.com/questions/796770/how-to-install-libopencl-so-on-ubuntu

Pause flag not present in cpuinfo?

The intel instruction set reference says:

This instruction was introduced in the Pentium 4 processors,
but is backward compatible with all IA-32 processors.
In earlier IA-32 processors, the PAUSE instruction operates
like a NOP instruction. The Pentium 4 and Intel Xeon processors
implement  the PAUSE instruction as a delay.

So your core 2 duo does have it, but even on processors that don't it will still work like a NOP.

#error SSE2 instruction set not enabled when including emmintrin.h

You need to call

set(CMAKE_C_FLAGS ${CMAKE_C_FLAGS} "-msse -msse2 -msse3")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse -msse2 -msse3")

The CMAKE_C_FLAGS are applied to C files, and from your post's C++ tag, I guess you're compiling C++ files, hence the need to change CMAKE_CXX_FLAGS instead.

As for the positioning of the quotation marks; in your original version, you were setting CMAKE_C_FLAGS to contain 2 separate entries, the first being the starting value of CMAKE_C_FLAGS and the second being the string "-msse -msse2 -msse3".

CMake holds lists like this as semi-colon separated entries. In the case of CMAKE_<lang>_FLAGS, invariably they are a single value comprised of a string containing all the required flags.

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