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January 30, 2021 04:32
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#include <cuda.h> | |
#include <stdio.h> | |
#define BLOCK_SIZE 32 | |
#define NUM_REPS 100 | |
inline void gpuAssert(cudaError_t err, const char *file, int line) | |
{ | |
if (err != cudaSuccess){ | |
printf("%s in %s at line %d\n", cudaGetErrorString(err), file, line); | |
exit(EXIT_FAILURE); | |
} | |
} | |
#define gpuErrchk(ans) \ | |
{ \ | |
gpuAssert((ans), __FILE__, __LINE__); \ | |
} | |
__global__ | |
void gpu_transpose_global(int* d_in, int* d_out, int M, int N){ | |
int col = blockIdx.x*blockDim.x + threadIdx.x; | |
int row = blockIdx.y*blockDim.y + threadIdx.y; | |
d_out[col*N + row] = d_in[row*N + col]; | |
} | |
__global__ | |
void gpu_transpose_shared(int* d_in, int* d_out, int M, int N){ | |
__shared__ int shmem[BLOCK_SIZE][BLOCK_SIZE]; | |
int col = blockIdx.x*blockDim.x + threadIdx.x; | |
int row = blockIdx.y*blockDim.y + threadIdx.y; | |
int tx=threadIdx.x, ty=threadIdx.y; | |
shmem[ty][tx] = d_in[row*N + col]; | |
__syncthreads(); | |
col = blockDim.x*blockIdx.y + threadIdx.x; | |
row = blockDim.y*blockIdx.x + threadIdx.y; | |
d_out[row*N + col] = shmem[tx][ty]; | |
} | |
__global__ | |
void gpu_transpose_shared_no_bankconflict(int* d_in, int* d_out, int M, int N){ | |
__shared__ int shmem[BLOCK_SIZE][BLOCK_SIZE+1]; | |
int col = blockIdx.x*blockDim.x + threadIdx.x; | |
int row = blockIdx.y*blockDim.y + threadIdx.y; | |
int tx=threadIdx.x, ty=threadIdx.y; | |
shmem[ty][tx] = d_in[row*N + col]; | |
__syncthreads(); | |
col = blockDim.x*blockIdx.y + threadIdx.x; | |
row = blockDim.y*blockIdx.x + threadIdx.y; | |
d_out[row*N + col] = shmem[tx][ty]; | |
} | |
void golden_model(int* input, int* output, int M, int N){ | |
for (int i=0; i<M; ++i){ | |
for(int j=0; j<N; ++j){ | |
output[N*j + i] = input[N*i + j]; | |
} | |
} | |
} | |
void postprocess(int *golden, int* gpu_out, int M, int N, float ms){ | |
for(int i=0; i<M*N; ++i){ | |
if (gpu_out[i] != golden[i]){ | |
printf("Mismatch: gpu: %d, cpu: %d, idx: %d \n", gpu_out[i], golden[i], i); | |
break; | |
} | |
} | |
printf("Effective time: %.3f ms\n", ms/NUM_REPS); | |
float bytes = sizeof(int)* 2 * (float)M * (float)N; | |
printf("Effective Bandwidth: %.3f Gbps\n", bytes * 1e-6* NUM_REPS /ms); | |
} | |
int main(){ | |
int M = 1024; | |
int N = 1024; | |
int *d_in, *d_out, *shd_out, *h_out; | |
gpuErrchk(cudaMallocManaged(&d_in, M*N*sizeof(int))); | |
gpuErrchk(cudaMallocManaged(&d_out, M*N*sizeof(int))); | |
gpuErrchk(cudaMallocManaged(&shd_out, M*N*sizeof(int))); | |
gpuErrchk(cudaMallocManaged(&h_out, M*N*sizeof(int))); | |
//Initialize | |
for (int i=0; i<M*N; ++i){ | |
d_in[i]=i; | |
d_out[i] = 0; | |
shd_out[i] = 0; | |
h_out[i] = 0; | |
} | |
golden_model(d_in, h_out, M, N); | |
dim3 blockSize (BLOCK_SIZE, BLOCK_SIZE,1); | |
dim3 gridSize ((N-1)/BLOCK_SIZE +1,(M-1)/BLOCK_SIZE + 1,1); | |
cudaEvent_t start, stop; | |
gpuErrchk(cudaEventCreate(&start)); | |
gpuErrchk(cudaEventCreate(&stop)); | |
/************ TRANSPOSE USING GLOBAL MEM **************/ | |
// warmup | |
gpu_transpose_global<<<gridSize, blockSize>>>(d_in, d_out, M, N); | |
gpuErrchk(cudaEventRecord(start)); | |
for (int i=0; i < NUM_REPS; ++i) | |
gpu_transpose_global<<<gridSize, blockSize>>>(d_in, d_out, M, N); | |
gpuErrchk(cudaEventRecord(stop)); | |
gpuErrchk(cudaEventSynchronize(stop)); | |
float milliseconds = 0; | |
gpuErrchk(cudaEventElapsedTime(&milliseconds, start, stop)); | |
printf("Transpose using Global Memory\n"); | |
postprocess(h_out, d_out, M, N, milliseconds); | |
printf("\n"); | |
/************ TRANSPOSE USING SHARED MEM **************/ | |
// warmup | |
gpu_transpose_shared<<<gridSize, blockSize>>>(d_in, shd_out, M, N); | |
gpuErrchk(cudaEventRecord(start)); | |
for (int i=0; i < NUM_REPS; ++i) | |
gpu_transpose_shared<<<gridSize, blockSize>>>(d_in, shd_out, M, N); | |
gpuErrchk(cudaEventRecord(stop)); | |
gpuErrchk(cudaEventSynchronize(stop)); | |
milliseconds = 0; | |
gpuErrchk(cudaEventElapsedTime(&milliseconds, start, stop)); | |
printf("Transpose using Shared Memory\n"); | |
postprocess(h_out, shd_out, M, N, milliseconds); | |
printf("\n"); | |
/************ TRANSPOSE USING SHARED MEM & NO BANK CONFLICT**************/ | |
// warmup | |
gpu_transpose_shared_no_bankconflict<<<gridSize, blockSize>>>(d_in, shd_out, M, N); | |
gpuErrchk(cudaEventRecord(start)); | |
for (int i=0; i < NUM_REPS; ++i) | |
gpu_transpose_shared_no_bankconflict<<<gridSize, blockSize>>>(d_in, shd_out, M, N); | |
gpuErrchk(cudaEventRecord(stop)); | |
gpuErrchk(cudaEventSynchronize(stop)); | |
milliseconds = 0; | |
gpuErrchk(cudaEventElapsedTime(&milliseconds, start, stop)); | |
printf("Transpose using Shared Memory and No bank conflict\n"); | |
postprocess(h_out, shd_out, M, N, milliseconds); | |
printf("\n"); | |
cudaFree(d_in); | |
cudaFree(d_out); | |
cudaFree(shd_out); | |
cudaFree(h_out); | |
return 0; | |
} |
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Compile Cmd:
nvcc -std=c++11 transpose.cu -o transpose.o && ./transpose.o
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