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/*
* Copyright (c) 2016 University of Cordoba and University of Illinois
* All rights reserved.
*
* Developed by: IMPACT Research Group
* University of Cordoba and University of Illinois
* http://impact.crhc.illinois.edu/
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* with the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* > Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimers.
* > Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimers in the
* documentation and/or other materials provided with the distribution.
* > Neither the names of IMPACT Research Group, University of Cordoba,
* University of Illinois nor the names of its contributors may be used
* to endorse or promote products derived from this Software without
* specific prior written permission.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH
* THE SOFTWARE.
*
*/
#define _CUDA_COMPILER_
#include "support/common.h"
#include "support/partitioner.h"
// CUDA kernel ------------------------------------------------------------------------------------------
__global__ void Histogram_kernel(int size, int bins, int n_tasks, float alpha, unsigned int *data,
unsigned int *histo
#ifdef CUDA_8_0
, int *worklist
#endif
) {
extern __shared__ unsigned int l_mem[];
unsigned int* l_histo = l_mem;
#ifdef CUDA_8_0
int* l_tmp = (int*)&l_histo[bins];
#endif
#ifdef CUDA_8_0
Partitioner p = partitioner_create(n_tasks, alpha, worklist, l_tmp);
#else
Partitioner p = partitioner_create(n_tasks, alpha);
#endif
// Block and thread index
const int bx = blockIdx.x;
const int tx = threadIdx.x;
const int bD = blockDim.x;
const int gD = gridDim.x;
// Sub-histograms initialization
for(int pos = tx; pos < bins; pos += bD) {
l_histo[pos] = 0;
}
__syncthreads(); // Intra-block synchronization
// Main loop
for(int i = gpu_first(&p); gpu_more(&p); i = gpu_next(&p)) {
// Global memory read
unsigned int d = data[i * bD + tx];
// Atomic vote in shared memory
atomicAdd(&l_histo[((d * bins) >> 12)], 1);
}
__syncthreads(); // Intra-block synchronization
// Merge per-block histograms and write to global memory
for(int pos = tx; pos < bins; pos += bD) {
// Atomic addition in global memory
#ifdef CUDA_8_0
atomicAdd_system(histo + pos, l_histo[pos]);
#else
atomicAdd(histo + pos, l_histo[pos]);
#endif
}
}
cudaError_t call_Histogram_kernel(int blocks, int threads, int size, int bins, int n_tasks, float alpha,
unsigned int *data, unsigned int *histo, int l_mem_size
#ifdef CUDA_8_0
, int* worklist
#endif
){
dim3 dimGrid(blocks);
dim3 dimBlock(threads);
Histogram_kernel<<<dimGrid, dimBlock, l_mem_size>>>(size, bins, n_tasks, alpha,
data, histo
#ifdef CUDA_8_0
, worklist
#endif
);
cudaError_t err = cudaGetLastError();
return err;
}
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