Open-Harbor/osrm-backend
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases 3 Wiki Activity

Removed SSE code in RangeTable to rely on compiler optimazation

Browse Source
This commit is contained in:
Patrick Niklaus 2014-06-11 01:28:31 +02:00
parent ef60ae652c
commit 4c17aeb180
1 changed files with 7 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

67
DataStructures/RangeTable.h
View File

@ -6,11 +6,6 @@
#include <fstream>
#include <vector>
#if defined(__GNUC__) && defined(__SSE2__)
#define OSRM_USE_SSE
#include <xmmintrin.h>
#endif
#include "SharedMemoryFactory.h"
#include "SharedMemoryVectorWrapper.h"
@ -40,16 +35,8 @@ template<unsigned BLOCK_SIZE, bool USE_SHARED_MEMORY>
class RangeTable
{
public:
union BlockT
{
unsigned char uint8_blocks[BLOCK_SIZE];
#ifdef OSRM_USE_SSE
static_assert(BLOCK_SIZE % 16 == 0,
"If SSE instructions are enabled, only multiples of 16 are supported as BLOCK_SIZE");
__m128i uint128_blocks[BLOCK_SIZE/16];
#endif
};
typedef std::array<unsigned char, BLOCK_SIZE> BlockT;
typedef typename ShM<BlockT, USE_SHARED_MEMORY>::vector BlockContainerT;
typedef typename ShM<unsigned, USE_SHARED_MEMORY>::vector OffsetContainerT;
typedef decltype(boost::irange(0u,0u)) RangeT;
@ -98,7 +85,7 @@ public:
}
else
{
block.uint8_blocks[block_idx - 1] = last_length;
block[block_idx - 1] = last_length;
block_sum += last_length;
}
@ -134,7 +121,7 @@ public:
while (block_idx != 0)
{
block.uint8_blocks[block_idx - 1] = last_length;
block[block_idx - 1] = last_length;
last_length = 0;
block_idx = (block_idx + 1) % (BLOCK_SIZE + 1);
}
@ -167,7 +154,7 @@ public:
if (internal_idx < BLOCK_SIZE)
{
// note internal_idx - 1 is the *current* index for uint8_blocks
end_idx = begin_idx + block.uint8_blocks[internal_idx];
end_idx = begin_idx + block[internal_idx];
}
else
{
@ -191,54 +178,14 @@ private:
unsigned sum_lengths;
};
#ifdef OSRM_USE_SSE
// For blocksize 16 we can use SSE instructions
// FIXME only implemented for non-shared memory
template<>
unsigned RangeTable<16>::PrefixSumAtIndex(int index, const BlockT& block) const
{
union OffsetT
{
unsigned short u16[8];
__m128i u128;
};
OffsetT offsets;
// converts lower 8 bytes to 8 shorts
offsets.u128 = _mm_unpacklo_epi8(block.uint128_blocks[0], _mm_set1_epi8(0));
offsets.u128 = _mm_add_epi16(offsets.u128, _mm_slli_si128(offsets.u128, 2));
if (index < 2)
return offsets.u16[index];
offsets.u128 = _mm_add_epi16(offsets.u128, _mm_slli_si128(offsets.u128, 4));
if (index < 4)
return offsets.u16[index];
offsets.u128 = _mm_add_epi16(offsets.u128, _mm_slli_si128(offsets.u128, 8));
if (index < 8)
return offsets.u16[index];
unsigned temp = offsets.u16[7];
index -= 8;
// converts upper 8 bytes to 8 shorts
offsets.u128 = _mm_unpackhi_epi8(block.uint128_blocks[0], _mm_set1_epi8(0));
offsets.u128 = _mm_add_epi16(offsets.u128, _mm_slli_si128(offsets.u128, 2));
if (index < 2)
return (temp + offsets.u16[index]);
offsets.u128 = _mm_add_epi16(offsets.u128, _mm_slli_si128(offsets.u128, 4));
if (index < 4)
return (temp + offsets.u16[index]);
offsets.u128 = _mm_add_epi16(offsets.u128, _mm_slli_si128(offsets.u128, 8));
return (temp + offsets.u16[index]);
}
#endif
template<unsigned BLOCK_SIZE, bool USE_SHARED_MEMORY>
unsigned RangeTable<BLOCK_SIZE, USE_SHARED_MEMORY>::PrefixSumAtIndex(int index, const BlockT& block) const
{
// this loop looks inefficent, but a modern compiler
// will emit nice SIMD here, at least for sensible block sizes. (I checked.)
unsigned sum = 0;
for (int i = 0; i <= index; i++)
sum += block.uint8_blocks[i];
sum += block[i];
return sum;
}