Classical Meyers Singleton

// singletonSingleThreaded.cpp
#include <chrono>
#include <iostream>
constexpr auto tenMill = 10000000;
class MySingleton{
public:
  static MySingleton& getInstance(){
    static MySingleton instance;
    volatile int dummy{};
    return instance;
  }
private:
  MySingleton() = default;
  ~MySingleton() = default;
  MySingleton(const MySingleton&) = delete;
  MySingleton& operator=(const MySingleton&) = delete;
  
};
int main(){
    
  constexpr auto fourtyMill = 4 * tenMill;
  
  const auto begin= std::chrono::system_clock::now();
  
  for ( size_t i = 0; i <= fourtyMill; ++i){
    MySingleton::getInstance();
  }
  
  const auto end = std::chrono::system_clock::now() - begin;
  
  std::cout << std::chrono::duration<double>(end).count() << std::endl;
}