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lerlinghagen
Journeyman III

OpenCL performance when rendering OpenGL on another GPU

Hi,

we're working on a real-time image processing application where we want to use an Intel Core as the host CPU, its integrated GPU for display rendering, and an AMD GPU (R9 285) for OpenCL processing. The OS is Windows 8.1, 64-bit.

However, we're seeing massive performance problems when the Intel GPU is the primary display adapter (and even when there is no monitor attached to the R9), and is used for OpenGL rendering. CodeXL's application timeline trace shows that our kernels and memory transfers do run fast enough, but that the R9 GPU and its command queue sit idle for quite some time in between the kernels. The OpenCL host thread waits inside a call to clFinish while this happens. This does not occur when the R9 is the primary display adapter and is used for rendering. There is no explicit OpenCL/OpenGL interop in our code.

Is there some kind of implicit synchronization between OpenCL and OpenGL going on here? If so, how can we detect and disable that?

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3 Replies
dipak
Big Boss

While checking some older threads, I found few issues which, somehow, fell through the cracks. This is one of them.

Just wanted to know whether your issue has been resolved or not?

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We have been able to resolve this by uninstalling both GPU drivers, then reinstalling the Intel GPU driver before installing the AMD GPU driver.

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Nice to hear that the problem has been resolve. Thanks for sharing the workaround.

Regards,

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