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HLSL Spin in GPU

Question asked by easizm on Aug 14, 2018

    Bitonic sort is a fast way to arange array in GPU. ShareMemory is benefit for small array to provide a synchronization,But there is no way to make a synchronization under different thread group.I have tried to do a spin in thread to wait for data has been processed.But I got result fiiled with zero.I guess it  can't be supported in GPU.Here is a part code.

void CompareAndExchange(uint fence, uint Top, uint Bottom)

{

while (true)

{

          //wait for flag has been add 1

            if (Atomic[Top] == fence && Atomic[Bottom] == fence)

               break;

}

if (SortArray[Top]>SortArray[Bottom] && Bottom<ArraySize)

{

  uint Temp = SortArray[Top];

  SortArray[Top] = SortArray[Bottom];

  SortArray[Bottom] = Temp;

}

//add 1 for next other thread

++Atomic[Top];

++Atomic[Bottom];

 

}

 

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