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Attached is an OpenCL kernel that triggers an awkward bug in Intel's OpenCL platform. On the same CPU it works on the AMD OpenCL platform, but not on the Intel OpenCL platform. This has been verified on multiple independent machines (all windows 7, both 32-bit and 64-bit). I have also added a tiny Netbeans project (with JOCL embedded) to provide full code to reproduce the bug. But if you don't use Netbeans, it's easy to reproduce anywhere by just feeding an empty float[100] to the kernel and reading it afterwards.
What the program does is simply executing the same program 4 times. What should happen is obviously that you get always the same output. However, on the Intel platform, somehow suddenly the first execution yields a different result. Always consequently the first, always consequently the same wrong output, on different machines. But the kernel itself is pretty trivial and has no memory at all over different executions.
I would classify this as a severe bug, since it doesn't just crash, but instead provides erroneous output without any notice!
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Raghupathi Muthyalampalli (Intel) wrote:Yes. On AMD platform, the output is always the same, for both CPU and GPU. On Intel, the first row is different: [0.0, 0.0, 0.0, 0.0, 0.5441741, 0.6534582, 0.9902577, 0.5279418, 0.7744405, 0.3976747, 0.734416, 0.0017434603, 0.22150545, 0.82592, [0.13983674, 0.39817378, 0.7858866, 0.90109515, 0.5441741, 0.6534582, 0.9902577, 0.5279418, 0.7744405, 0.3976747, 0.734416, [0.13983674, 0.39817378, 0.7858866, 0.90109515, 0.5441741, 0.6534582, 0.9902577, 0.5279418, 0.7744405, 0.3976747, 0.734416, [0.13983674, 0.39817378, 0.7858866, 0.90109515, 0.5441741, 0.6534582, 0.9902577, 0.5279418, 0.7744405, 0.3976747, 0.734416,
Just making sure...you get the same result for each iteration on other platforms right?
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Raghupathi Muthyalampalli (Intel) wrote:I used the most recent version at the time of my initial post. I'm glad to hear that Intel has solved the problem in their newest internal version. When will this internal version be ready for download?Can you let me know what version of the CPU runtime you have? I have verified that the later version (I am using an internal version) of the CPU runtime outputs correct values consistently.
Thanks,
Raghu

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