49 lines
1.7 KiB
C++
49 lines
1.7 KiB
C++
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#include <iostream>
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#include <hip_runtime.h>
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#define HIP_ASSERT(x) (assert((x)==hipSuccess))
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__global__ void
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gpu_ballot(hipLaunchParm lp, unsigned int* device_ballot, int Num_Warps_per_Block)
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{
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int tid = hipThreadIdx_x + hipBlockIdx_x * hipBlockDim_x;
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const unsigned int warp_num = hipThreadIdx_x >> 6;
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atomicAdd(&device_ballot[warp_num+hipBlockIdx_x*Num_Warps_per_Block],__popcll(__ballot(tid - 245)));
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}
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int main(int argc, char *argv[])
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{
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unsigned int Num_Threads_per_Block = 512;
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unsigned int Num_Blocks_per_Grid = 1;
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unsigned int Num_Warps_per_Block = Num_Threads_per_Block/64;
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unsigned int Num_Warps_per_Grid = (Num_Threads_per_Block*Num_Blocks_per_Grid)/64;
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unsigned int* host_ballot = (unsigned int*)malloc(Num_Warps_per_Grid*sizeof(unsigned int));
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unsigned int* device_ballot;
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HIP_ASSERT(hipMalloc((void**)&device_ballot, Num_Warps_per_Grid*sizeof(unsigned int)));
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for (int i=0; i<Num_Warps_per_Grid; i++) host_ballot[i] = 0;
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HIP_ASSERT(hipMemcpy(device_ballot, host_ballot, Num_Warps_per_Grid*sizeof(unsigned int), hipMemcpyHostToDevice));
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hipLaunchKernel(gpu_ballot, dim3(Num_Blocks_per_Grid),dim3(Num_Threads_per_Block),0,0, device_ballot,Num_Warps_per_Block);
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HIP_ASSERT(hipMemcpy(host_ballot, device_ballot, Num_Warps_per_Grid*sizeof(unsigned int), hipMemcpyDeviceToHost));
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for (int i=0; i<Num_Warps_per_Grid; i++) {
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if ((host_ballot[i] == 0)||(host_ballot[i]/64 == 64)) std::cout << "Warp " << i << " IS convergent- Predicate true for " << host_ballot[i]/64 << " threads\n";
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else std::cout << "Warp " << i << " IS divergent - Predicate true for " << host_ballot[i]/64<< " threads\n";
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}
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return EXIT_SUCCESS;
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}
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