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ispc/examples_ptx/bitonicSort/bitonicSort.cu
2014-01-27 14:02:42 +01:00

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/*
* Copyright 1993-2010 NVIDIA Corporation. All rights reserved.
*
* Please refer to the NVIDIA end user license agreement (EULA) associated
* with this source code for terms and conditions that govern your use of
* this software. Any use, reproduction, disclosure, or distribution of
* this software and related documentation outside the terms of the EULA
* is strictly prohibited.
*
*/
//Based on http://www.iti.fh-flensburg.de/lang/algorithmen/sortieren/bitonic/bitonicen.htm
#include <assert.h>
#include <cutil_inline.h>
#include "sortingNetworks_common.h"
#include "sortingNetworks_common.cuh"
////////////////////////////////////////////////////////////////////////////////
// Monolithic bitonic sort kernel for short arrays fitting into shared memory
////////////////////////////////////////////////////////////////////////////////
__global__ void bitonicSortShared(
uint *d_DstKey,
uint *d_DstVal,
uint *d_SrcKey,
uint *d_SrcVal,
uint arrayLength,
uint dir
){
//Shared memory storage for one or more short vectors
__shared__ uint s_key[SHARED_SIZE_LIMIT];
__shared__ uint s_val[SHARED_SIZE_LIMIT];
//Offset to the beginning of subbatch and load data
d_SrcKey += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_SrcVal += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_DstKey += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_DstVal += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
s_key[threadIdx.x + 0] = d_SrcKey[ 0];
s_val[threadIdx.x + 0] = d_SrcVal[ 0];
s_key[threadIdx.x + (SHARED_SIZE_LIMIT / 2)] = d_SrcKey[(SHARED_SIZE_LIMIT / 2)];
s_val[threadIdx.x + (SHARED_SIZE_LIMIT / 2)] = d_SrcVal[(SHARED_SIZE_LIMIT / 2)];
for(uint size = 2; size < arrayLength; size <<= 1){
//Bitonic merge
uint ddd = dir ^ ( (threadIdx.x & (size / 2)) != 0 );
for(uint stride = size / 2; stride > 0; stride >>= 1){
__syncthreads();
uint pos = 2 * threadIdx.x - (threadIdx.x & (stride - 1));
Comparator(
s_key[pos + 0], s_val[pos + 0],
s_key[pos + stride], s_val[pos + stride],
ddd
);
}
}
//ddd == dir for the last bitonic merge step
{
for(uint stride = arrayLength / 2; stride > 0; stride >>= 1){
__syncthreads();
uint pos = 2 * threadIdx.x - (threadIdx.x & (stride - 1));
Comparator(
s_key[pos + 0], s_val[pos + 0],
s_key[pos + stride], s_val[pos + stride],
dir
);
}
}
__syncthreads();
d_DstKey[ 0] = s_key[threadIdx.x + 0];
d_DstVal[ 0] = s_val[threadIdx.x + 0];
d_DstKey[(SHARED_SIZE_LIMIT / 2)] = s_key[threadIdx.x + (SHARED_SIZE_LIMIT / 2)];
d_DstVal[(SHARED_SIZE_LIMIT / 2)] = s_val[threadIdx.x + (SHARED_SIZE_LIMIT / 2)];
}
////////////////////////////////////////////////////////////////////////////////
// Bitonic sort kernel for large arrays (not fitting into shared memory)
////////////////////////////////////////////////////////////////////////////////
//Bottom-level bitonic sort
//Almost the same as bitonicSortShared with the exception of
//even / odd subarrays being sorted in opposite directions
//Bitonic merge accepts both
//Ascending | descending or descending | ascending sorted pairs
__global__ void bitonicSortShared1(
uint *d_DstKey,
uint *d_DstVal,
uint *d_SrcKey,
uint *d_SrcVal
){
//Shared memory storage for current subarray
__shared__ uint s_key[SHARED_SIZE_LIMIT];
__shared__ uint s_val[SHARED_SIZE_LIMIT];
//Offset to the beginning of subarray and load data
d_SrcKey += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_SrcVal += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_DstKey += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_DstVal += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
s_key[threadIdx.x + 0] = d_SrcKey[ 0];
s_val[threadIdx.x + 0] = d_SrcVal[ 0];
s_key[threadIdx.x + (SHARED_SIZE_LIMIT / 2)] = d_SrcKey[(SHARED_SIZE_LIMIT / 2)];
s_val[threadIdx.x + (SHARED_SIZE_LIMIT / 2)] = d_SrcVal[(SHARED_SIZE_LIMIT / 2)];
for(uint size = 2; size < SHARED_SIZE_LIMIT; size <<= 1){
//Bitonic merge
uint ddd = (threadIdx.x & (size / 2)) != 0;
for(uint stride = size / 2; stride > 0; stride >>= 1){
__syncthreads();
uint pos = 2 * threadIdx.x - (threadIdx.x & (stride - 1));
Comparator(
s_key[pos + 0], s_val[pos + 0],
s_key[pos + stride], s_val[pos + stride],
ddd
);
}
}
//Odd / even arrays of SHARED_SIZE_LIMIT elements
//sorted in opposite directions
uint ddd = blockIdx.x & 1;
{
for(uint stride = SHARED_SIZE_LIMIT / 2; stride > 0; stride >>= 1){
__syncthreads();
uint pos = 2 * threadIdx.x - (threadIdx.x & (stride - 1));
Comparator(
s_key[pos + 0], s_val[pos + 0],
s_key[pos + stride], s_val[pos + stride],
ddd
);
}
}
__syncthreads();
d_DstKey[ 0] = s_key[threadIdx.x + 0];
d_DstVal[ 0] = s_val[threadIdx.x + 0];
d_DstKey[(SHARED_SIZE_LIMIT / 2)] = s_key[threadIdx.x + (SHARED_SIZE_LIMIT / 2)];
d_DstVal[(SHARED_SIZE_LIMIT / 2)] = s_val[threadIdx.x + (SHARED_SIZE_LIMIT / 2)];
}
//Bitonic merge iteration for stride >= SHARED_SIZE_LIMIT
__global__ void bitonicMergeGlobal(
uint *d_DstKey,
uint *d_DstVal,
uint *d_SrcKey,
uint *d_SrcVal,
uint arrayLength,
uint size,
uint stride,
uint dir
){
uint global_comparatorI = blockIdx.x * blockDim.x + threadIdx.x;
uint comparatorI = global_comparatorI & (arrayLength / 2 - 1);
//Bitonic merge
uint ddd = dir ^ ( (comparatorI & (size / 2)) != 0 );
uint pos = 2 * global_comparatorI - (global_comparatorI & (stride - 1));
uint keyA = d_SrcKey[pos + 0];
uint valA = d_SrcVal[pos + 0];
uint keyB = d_SrcKey[pos + stride];
uint valB = d_SrcVal[pos + stride];
Comparator(
keyA, valA,
keyB, valB,
ddd
);
d_DstKey[pos + 0] = keyA;
d_DstVal[pos + 0] = valA;
d_DstKey[pos + stride] = keyB;
d_DstVal[pos + stride] = valB;
}
//Combined bitonic merge steps for
//size > SHARED_SIZE_LIMIT and stride = [1 .. SHARED_SIZE_LIMIT / 2]
__global__ void bitonicMergeShared(
uint *d_DstKey,
uint *d_DstVal,
uint *d_SrcKey,
uint *d_SrcVal,
uint arrayLength,
uint size,
uint dir
){
//Shared memory storage for current subarray
__shared__ uint s_key[SHARED_SIZE_LIMIT];
__shared__ uint s_val[SHARED_SIZE_LIMIT];
d_SrcKey += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_SrcVal += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_DstKey += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
d_DstVal += blockIdx.x * SHARED_SIZE_LIMIT + threadIdx.x;
s_key[threadIdx.x + 0] = d_SrcKey[ 0];
s_val[threadIdx.x + 0] = d_SrcVal[ 0];
s_key[threadIdx.x + (SHARED_SIZE_LIMIT / 2)] = d_SrcKey[(SHARED_SIZE_LIMIT / 2)];
s_val[threadIdx.x + (SHARED_SIZE_LIMIT / 2)] = d_SrcVal[(SHARED_SIZE_LIMIT / 2)];
//Bitonic merge
uint comparatorI = UMAD(blockIdx.x, blockDim.x, threadIdx.x) & ((arrayLength / 2) - 1);
uint ddd = dir ^ ( (comparatorI & (size / 2)) != 0 );
for(uint stride = SHARED_SIZE_LIMIT / 2; stride > 0; stride >>= 1){
__syncthreads();
uint pos = 2 * threadIdx.x - (threadIdx.x & (stride - 1));
Comparator(
s_key[pos + 0], s_val[pos + 0],
s_key[pos + stride], s_val[pos + stride],
ddd
);
}
__syncthreads();
d_DstKey[ 0] = s_key[threadIdx.x + 0];
d_DstVal[ 0] = s_val[threadIdx.x + 0];
d_DstKey[(SHARED_SIZE_LIMIT / 2)] = s_key[threadIdx.x + (SHARED_SIZE_LIMIT / 2)];
d_DstVal[(SHARED_SIZE_LIMIT / 2)] = s_val[threadIdx.x + (SHARED_SIZE_LIMIT / 2)];
}
////////////////////////////////////////////////////////////////////////////////
// Interface function
////////////////////////////////////////////////////////////////////////////////
//Helper function (also used by odd-even merge sort)
extern "C" uint factorRadix2(uint *log2L, uint L){
if(!L){
*log2L = 0;
return 0;
}else{
for(*log2L = 0; (L & 1) == 0; L >>= 1, *log2L++);
return L;
}
}
extern "C" uint bitonicSort(
uint *d_DstKey,
uint *d_DstVal,
uint *d_SrcKey,
uint *d_SrcVal,
uint batchSize,
uint arrayLength,
uint dir
){
//Nothing to sort
if(arrayLength < 2)
return 0;
//Only power-of-two array lengths are supported by this implementation
uint log2L;
uint factorizationRemainder = factorRadix2(&log2L, arrayLength);
assert( factorizationRemainder == 1 );
dir = (dir != 0);
uint blockCount = batchSize * arrayLength / SHARED_SIZE_LIMIT;
uint threadCount = SHARED_SIZE_LIMIT / 2;
if(arrayLength <= SHARED_SIZE_LIMIT){
assert( (batchSize * arrayLength) % SHARED_SIZE_LIMIT == 0 );
bitonicSortShared<<<blockCount, threadCount>>>(d_DstKey, d_DstVal, d_SrcKey, d_SrcVal, arrayLength, dir);
}else{
bitonicSortShared1<<<blockCount, threadCount>>>(d_DstKey, d_DstVal, d_SrcKey, d_SrcVal);
for(uint size = 2 * SHARED_SIZE_LIMIT; size <= arrayLength; size <<= 1)
for(unsigned stride = size / 2; stride > 0; stride >>= 1)
if(stride >= SHARED_SIZE_LIMIT){
bitonicMergeGlobal<<<(batchSize * arrayLength) / 512, 256>>>(d_DstKey, d_DstVal, d_DstKey, d_DstVal, arrayLength, size, stride, dir);
}else{
bitonicMergeShared<<<blockCount, threadCount>>>(d_DstKey, d_DstVal, d_DstKey, d_DstVal, arrayLength, size, dir);
break;
}
}
return threadCount;
}
extern "C" int isDeviceEmulation(void){
#ifdef __DEVICE_EMULATION__
return 1;
#else
return 0;
#endif
}