From de618bf97493b295a57de3165c0d7098f0062a6e Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Mon, 6 Jun 2022 22:08:55 +0300
Subject: [PATCH] Add benchmark/unordered.cpp

---
 benchmark/unordered.cpp | 306 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 306 insertions(+)
 create mode 100644 benchmark/unordered.cpp

diff --git a/benchmark/unordered.cpp b/benchmark/unordered.cpp
new file mode 100644
index 0000000..c8b23b9
--- /dev/null
+++ b/benchmark/unordered.cpp
@@ -0,0 +1,306 @@
+// Copyright 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <boost/container_hash/hash.hpp>
+#include <boost/unordered_set.hpp>
+#include <boost/core/detail/splitmix64.hpp>
+#include <boost/core/type_name.hpp>
+#include <boost/config.hpp>
+#include <cstddef>
+#include <cstdio>
+#include <cstdint>
+#include <string>
+#include <vector>
+#include <chrono>
+#include <functional>
+
+// mul31_hash
+
+class mul31_hash
+{
+public:
+
+    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
+
+        for( std::size_t i = 0; i < n; ++i )
+        {
+            h = h * 31 + static_cast<unsigned char>( p[i] );
+        }
+
+        return h;
+    }
+};
+
+// mul31_unrolled_hash
+
+template<int Bits> struct mul31_unrolled_hash_impl;
+
+template<> struct mul31_unrolled_hash_impl<32>
+{
+    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 = 0x811C9DC5u;
+
+        while( n >= 4 )
+        {
+            h = h * (31u * 31u * 31u * 31u)
+                + static_cast<unsigned char>( p[0] ) * (31u * 31u * 31u)
+                + static_cast<unsigned char>( p[1] ) * (31u * 31u)
+                + static_cast<unsigned char>( p[2] ) * 31u
+                + static_cast<unsigned char>( p[3] );
+
+            p += 4;
+            n -= 4;
+        }
+
+        while( n > 0 )
+        {
+            h = h * 31u + static_cast<unsigned char>( *p );
+
+            ++p;
+            --n;
+        }
+
+        return h;
+    }
+};
+
+template<> struct mul31_unrolled_hash_impl<64>
+{
+    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;
+
+        while( n >= 8 )
+        {
+            h = h * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
+                + static_cast<unsigned char>( p[0] ) * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
+                + static_cast<unsigned char>( p[1] ) * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
+                + static_cast<unsigned char>( p[2] ) * (31ull * 31ull * 31ull * 31ull * 31ull)
+                + static_cast<unsigned char>( p[3] ) * (31ull * 31ull * 31ull * 31ull)
+                + static_cast<unsigned char>( p[4] ) * (31ull * 31ull * 31ull)
+                + static_cast<unsigned char>( p[5] ) * (31ull * 31ull)
+                + static_cast<unsigned char>( p[6] ) * 31ull
+                + static_cast<unsigned char>( p[7] );
+
+            p += 8;
+            n -= 8;
+        }
+
+        while( n > 0 )
+        {
+            h = h * 31u + static_cast<unsigned char>( *p );
+
+            ++p;
+            --n;
+        }
+
+        return 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;
+
+template<> struct fnv1a_hash_impl<32>
+{
+    std::size_t operator()( std::string const& s ) const
+    {
+        std::size_t h = 0x811C9DC5u;
+
+        char const * first = s.data();
+        char const * last = first + s.size();
+
+        for( ; first != last; ++first )
+        {
+            h ^= static_cast<unsigned char>( *first );
+            h *= 0x01000193ul;
+        }
+
+        return h;
+    }
+};
+
+template<> struct fnv1a_hash_impl<64>
+{
+    std::size_t operator()( std::string const& s ) const
+    {
+        std::size_t h = 0xCBF29CE484222325ull;
+
+        char const * first = s.data();
+        char const * last = first + s.size();
+
+        for( ; first != last; ++first )
+        {
+            h ^= static_cast<unsigned char>( *first );
+            h *= 0x00000100000001B3ull;
+        }
+
+        return h;
+    }
+};
+
+struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits > {};
+
+//
+
+template<class V, class S> void test4( int N, V const& v, char const * hash, S s )
+{
+    typedef std::chrono::steady_clock clock_type;
+
+    clock_type::time_point t1 = clock_type::now();
+
+    for( int i = 0; i < N; ++i )
+    {
+        s.insert( v[ i * 16 ] );
+    }
+
+    clock_type::time_point t2 = clock_type::now();
+
+    std::size_t q = 0;
+
+    for( int i = 0; i < 16 * N; ++i )
+    {
+        q += s.count( v[ i ] );
+    }
+
+    clock_type::time_point t3 = clock_type::now();
+
+    long long ms1 = std::chrono::duration_cast<std::chrono::milliseconds>( t2 - t1 ).count();
+    long long ms2 = std::chrono::duration_cast<std::chrono::milliseconds>( t3 - t2 ).count();
+
+    std::size_t n = s.bucket_count();
+    std::size_t m = 0;
+
+    for( std::size_t i = 0; i < n; ++i )
+    {
+        std::size_t k = s.bucket_size( i );
+
+        if( k > m )
+        {
+            m = k;
+        }
+    }
+
+#if defined( _MSC_VER )
+
+    std::printf( "%25s : n=%Iu, m=%Iu, q=%Iu, %lld + %lld ms\n", hash, n, m, q, ms1, ms2 );
+
+#else
+
+    std::printf( "%25s : n=%zu, m=%zu, q=%zu, %lld + %lld ms\n", hash, n, m, q, ms1, ms2 );
+
+#endif
+}
+
+template<class K, class H, class V> void test3( int N, V const& v )
+{
+    boost::unordered_set<K, H> s( 0 );
+    test4( N, v, boost::core::type_name<H>().c_str(), s );
+}
+
+template<class H, class V> void test2( int N, V const& v )
+{
+    typedef std::chrono::steady_clock clock_type;
+
+    clock_type::time_point t1 = clock_type::now();
+
+    std::size_t q = 0;
+
+    H const h;
+
+    for( int i = 0; i < N; ++i )
+    {
+        q += h( v[i] );
+    }
+
+    clock_type::time_point t2 = clock_type::now();
+
+    long long ms1 = std::chrono::duration_cast<std::chrono::milliseconds>( t2 - t1 ).count();
+
+    std::string hash = boost::core::type_name<H>();
+
+#if defined( _MSC_VER )
+
+    std::printf( "%25s : q=%20Iu, %lld ms\n", hash.c_str(), q, ms1 );
+
+#else
+
+    std::printf( "%25s : q=%20zu, %lld ms\n", hash.c_str(), q, ms1 );
+
+#endif
+}
+
+int main()
+{
+    int const N = 1048576;
+
+    std::vector<std::string> v;
+
+    {
+        v.reserve( N * 16 );
+
+        boost::detail::splitmix64 rnd;
+
+        for( int i = 0; i < 16 * N; ++i )
+        {
+            char buffer[ 64 ];
+
+            unsigned long long k = rnd();
+
+            if( k & 1 )
+            {
+                sprintf( buffer, "prefix_%llu_suffix", k );
+            }
+            else
+            {
+                sprintf( buffer, "{%u}", static_cast<unsigned>( k ) );
+            }
+
+            v.push_back( buffer );
+        }
+    }
+
+    typedef std::string K;
+
+    std::puts( "Hash speed test:\n" );
+
+    test2<mul31_hash>( N * 16, v );
+    test2<mul31_unrolled_hash>( N * 16, v );
+    test2<fnv1a_hash>( N * 16, v );
+    test2<boost::hash<std::string> >( N * 16, v );
+    test2<std::hash<std::string> >( N * 16, v );
+
+    std::puts( "" );
+
+    std::puts( "Container speed test:\n" );
+
+    test3<K, mul31_hash>( N, v );
+    test3<K, mul31_unrolled_hash>( N, v );
+    test3<K, fnv1a_hash>( N, v );
+    test3<K, boost::hash<std::string> >( N, v );
+    test3<K, std::hash<std::string> >( N, v );
+
+    std::puts( "" );
+}