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Split mul31_unrolled_hash into mul31_x4_hash and mul31_x8_hash in benchmarks

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This commit is contained in:
Peter Dimov
2022-11-25 20:52:30 +02:00
parent ffadafa0c1
commit 251894540d
2 changed files with 36 additions and 31 deletions
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benchmark/unordered.cpp
+18 -15
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@@ -26,10 +26,8 @@
// mul31_hash
class mul31_hash
struct mul31_hash
{
public:
std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
{
char const * p = st.data();
@@ -50,18 +48,20 @@ public:
}
};
// mul31_unrolled_hash
// mul31_x4_hash
template<int Bits> struct mul31_unrolled_hash_impl;
template<> struct mul31_unrolled_hash_impl<32>
struct mul31_x4_hash
{
std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
{
char const * p = st.data();
std::size_t n = st.size();
#if SIZE_MAX > UINT32_MAX
std::size_t h = 0xCBF29CE484222325ull;
#else
std::size_t h = 0x811C9DC5u;
#endif
while( n >= 4 )
{
@@ -87,14 +87,16 @@ template<> struct mul31_unrolled_hash_impl<32>
}
};
template<> struct mul31_unrolled_hash_impl<64>
// mul31_x8_hash
struct mul31_x8_hash
{
std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
{
char const * p = st.data();
std::size_t n = st.size();
std::size_t h = 0xCBF29CE484222325ull;
boost::uint64_t h = 0xCBF29CE484222325ull;
while( n >= 8 )
{
@@ -120,12 +122,10 @@ template<> struct mul31_unrolled_hash_impl<64>
--n;
}
return h;
return static_cast<std::size_t>( h );
}
};
struct mul31_unrolled_hash: mul31_unrolled_hash_impl< std::numeric_limits<std::size_t>::digits > {};
// fnv1a_hash
template<int Bits> struct fnv1a_hash_impl;
@@ -363,7 +363,8 @@ int main()
std::puts( "Hash speed test:\n" );
test_hash_speed<mul31_hash>( N * 16, v );
test_hash_speed<mul31_unrolled_hash>( N * 16, v );
test_hash_speed<mul31_x4_hash>( N * 16, v );
test_hash_speed<mul31_x8_hash>( N * 16, v );
test_hash_speed<fnv1a_hash>( N * 16, v );
test_hash_speed<boost::hash<std::string> >( N * 16, v );
test_hash_speed<std::hash<std::string> >( N * 16, v );
@@ -396,7 +397,8 @@ int main()
}
test_hash_collision<mul31_hash>( N * 16, v, n );
test_hash_collision<mul31_unrolled_hash>( N * 16, v, n );
test_hash_collision<mul31_x4_hash>( N * 16, v, n );
test_hash_collision<mul31_x8_hash>( N * 16, v, n );
test_hash_collision<fnv1a_hash>( N * 16, v, n );
test_hash_collision<boost::hash<std::string> >( N * 16, v, n );
test_hash_collision<std::hash<std::string> >( N * 16, v, n );
@@ -418,7 +420,8 @@ int main()
std::puts( "Container speed test:\n" );
test_container_speed<K, mul31_hash>( N, v );
test_container_speed<K, mul31_unrolled_hash>( N, v );
test_container_speed<K, mul31_x4_hash>( N, v );
test_container_speed<K, mul31_x8_hash>( N, v );
test_container_speed<K, fnv1a_hash>( N, v );
test_container_speed<K, boost::hash<std::string> >( N, v );
test_container_speed<K, std::hash<std::string> >( N, v );