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#Actualphantom

Posted 31 January 2013 - 03:53 PM

I'm not convinced you are using the GPU how you think you are.

While you are telling OpenCL to launch 0x4000000 threads you are telling it that each work group consists of a single thread, which means you are wasting a vast amount of GPU resources as it will be launching 'preferred_work_group_size_multiple * 0x4000000' warps or wave fronts but only using one thread in each one.

If you run 'clinfo' in a cmd window you should get told the preferred work group size multiple; set the local_ws value to that and you should end up using all the GPU threads instead of just one in each warp/wave front launched.
(For example on my card this value is 64, so a work group of less than 64 is going to waste resources.)

#1phantom

Posted 31 January 2013 - 03:53 PM

I'm not convinced you are using the GPU how you think you are.

 

While you are telling OpenCL to launch 0x4000000 threads you are telling it that each work group consists of a single thread, which means you are wasting a vast amount of GPU resources as it will be launching 'preferred_work_group_size_multiple * 0x4000000' warps or wave fronts but only using one thread in each one.

 

If you run 'clinfo' in a cmd window you should get told the preferred work group size multiple; set the local_ws value to that and you should end up using all the GPU threads instead of just one in each warp/wave front launched.


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