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Adept I

Concurrent kernel execution and OpenCL device partition

Recently I needed to do some experiments which need run multiple different kernel on AMD hardware. But I have several questions before starting to coding hence I really need your help.

First, I am not quite sure whether AMD HW can support concurrent kernel execution on one device. Because when I refer to the OpenCL specs, they said the command queue can be created as in-order and out-of-order. But I don't "out-of-order" mean "concurrent execution". Is there anyone know info about this? My hardware is AMD APU A8 3870k. If this processor does not support, any other AMD products support?

Second, I know there is an extension "device fission" which can be used to partition one device into two devices. This works only on CPU now. But in OpenCL specs, I saw something, i.e. "clcreatesubdevice", which is also used to partition one device into two? So my question is is there any difference between these two techniques? My understanding is: device fission can only be used on CPU, clcreatesubdevice can be used on both the CPU and the GPU. Is that correct?

Thanks for any kind reply!

1 Reply

AFAIK there is no OpenCL implementation that support out of order queues.

device fission is clCreateSubDevice() call so it is usable only on AMD CPU. IIRC Intel OpenCL implemetation should support device fission on CPU too. currently there is no way to execute two kernels concurrently on single AMD GPU. you can only gain concurrent transfer and kernel execution.