unordered_map mircro-benchmark

#include <iostream>
#include <limits>
#include <vector>
#include <unordered_map>
#include <map>
#include <chrono>

#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int_distribution.hpp>

#include <google/dense_hash_map>
#include <google/sparsehash/libc_allocator_with_realloc.h>

#include "concurrent_map.h"

static constexpr int SIZE = 10000000;

void bench() {
    boost::random::mt19937 rng;
    boost::random::uniform_int_distribution<> dist(std::numeric_limits<uint64_t>::min(), std::numeric_limits<uint64_t>::max());
    std::vector<uint64_t> vec(SIZE);
    for (int i = 0; i < SIZE; ++i) {
        uint64_t val = 0;
        while (val == 0) {
            val = dist(rng);
        }
        vec[i] = val;
    }
    std:unordered_map<int, long double> map;
    //google::dense_hash_map<int, long double> map;
    //map.set_empty_key(0);
    auto begin = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < SIZE; ++i) {
        map[vec[i]] = 0.0;
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin);
    std::cout << "inserts: " << elapsed.count() << std::endl;
    std::random_shuffle(vec.begin(), vec.end());
    begin = std::chrono::high_resolution_clock::now();
    long double val;
    for (int i = 0; i < SIZE; ++i) {
        val = map[vec[i]];
    }
    end = std::chrono::high_resolution_clock::now();
    elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin);
    std::cout << "get: " << elapsed.count() << std::endl;
}

int main()
{
    bench();
}