Broadwell IGP needs more sub_group functions

OpenCL 2.0 has no support for a "ballot" style sub-group function.  A ballot returns bitmask containing the conditional flag for each "lane" in the sub-group.  As long as the sub-group (SIMD) size is 32 or less then this fits in a cl_uint.

Presumably sub-group any() and all() are implemented on Broadwell IGP by returning an ARF flag register?

It would be great if Broadwell IGP unofficially implemented sub_group_any() by returning the actual flag bitmask so that developers could apply popcount() and other operations to the mask.

Kernel optimization with oclopt and ico64


I work with the CLI tool of the Intel OpenCL SDK 1.2 on Scientific Linux. I'm interested in optimize my kernels (1) with the oclopt program and (2) with assembly code for CPU or MIC.

Question (1): How I understand the tool oclopt currently: the tool takes a builded spir code and some optimization methods like prefetching or loop-unrolling and produces an optimized version of it. Example:

Help! While using Kernel Builder for OpenCL API to debug, it shows CPU version are not supported by KDB...

As the image shows below, I've set the input arrayA, B and the output arrayC, then click the debug button, and Error occur.

Since I am new in OpenCL, I don't know how to solve this problem, so is there anyone who can help me? Thanks a lot!


Why I can see 2 platforms?


My computer has only 1 CPU. It has 4 cores (8 threads). But when I use   err = clGetPlatformIDs(0, NULL, &numPlatforms);, I get 2 platforms.

One platform contains 1 CPU and 1 GPU, the other one contains 1 CPU. The 2 CPU are the same CPU.

I don't know why.


The platform number :  2
        PlatformId=0 deviceNums=2 vedor:Intel(R) Corporation
        PlatformId=1 deviceNums=1 vedor:Intel(R) Corporation

Problem with MACROS added with clBuildProgram

Hi to everyone,

I have a problem with the SDK plugin for Visual Studio 2010. In my kernel I add several MACROS using the -D flag inside the options argument of the clBuildProgram function. However, this is not recognized by the Intel OpenCL SDK plugin, therefore it throws several "use of undeclared identifier" errors and I am not able to run my program.

OpenCL tools: kernel compilation stats and crashes

Hi, I'm new to Intel Iris graphics 5100 and Intel tool set, if my question is duplicated, please point me to original ones ;-)

Q1, how to generate kernel statistics? Code-Builder exposes II and ASM, but I haven't found stats, such as # of full ALU/half ALU, Nops, global/local st, etc. This would be helpful in my kernel tuning. I would assume Intel exposes it, since the ASM are exposed. 

Does Intel HD Graphics 5300 support OpenCL2.0 Fine-grained SVM?

I have Dell Venue 11 Pro 7140 tablet with Intel Core M (Intel HD Graphics 5300). I have installed OpenCL SDK 2014 Release 2.

When I run the sample code intel_ocl_svmbasic\SVMBasicFineGrained from

It shows my Graphics 5300 doesn't support fine-grained SVM. From the reference manual, it says it do support. Anything wrong?

Iscriversi a OpenCL*