Open-Harbor/osrm-backend
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Make storage blocks aligned to 4 bytes for ARM NEON/VFP instructions

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Aligned blocks prevent bus errors in NEON/VFP instructions.

Block pointers are aligned to 4 bytes, that is guaranteed
by aligned mmaped-pointers, the 4 bytes size of the CANARY block and
aligned sizes of blocks.
This commit is contained in:
Michael Krasnyk 2016-06-12 18:05:21 +02:00
parent 12d4832037
commit 04e334e3e2
No known key found for this signature in database
GPG Key ID: 3854C9454FE00649
2 changed files with 10 additions and 5 deletions
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13
include/storage/shared_datatype.hpp
View File

@ -14,7 +14,7 @@ namespace storage
{
// Added at the start and end of each block as sanity check
const constexpr char CANARY[] = "OSRM";
const constexpr char CANARY[4] = {'O', 'S', 'R', 'M'};
struct SharedDataLayout
{
@ -63,15 +63,20 @@ struct SharedDataLayout
entry_size[bid] = sizeof(T);
}
inline uint64_t AlignBlockSize(uint64_t block_size) const
{
const uint64_t alignment = 4;
return (block_size + (alignment - 1)) & ~(alignment - 1);
}
inline uint64_t GetBlockSize(BlockID bid) const
{
// special bit encoding
if (bid == CORE_MARKER)
{
return (num_entries[bid] / 32 + 1) * entry_size[bid];
return AlignBlockSize((num_entries[bid] / 32 + 1) * entry_size[bid]);
}
return num_entries[bid] * entry_size[bid];
return AlignBlockSize(num_entries[bid] * entry_size[bid]);
}
inline uint64_t GetSizeOfLayout() const

2
src/storage/storage.cpp
View File

@ -426,7 +426,7 @@ int Storage::Run()
unsigned temp_length;
name_stream.read((char *)&temp_length, sizeof(unsigned));
BOOST_ASSERT_MSG(temp_length ==
BOOST_ASSERT_MSG(shared_layout_ptr->AlignBlockSize(temp_length) ==
shared_layout_ptr->GetBlockSize(SharedDataLayout::NAME_CHAR_LIST),
"Name file corrupted!");