Resolution of std::chrono::high_resolution_clock doesn’t correspond to measurements

by

I’m going to guess you are using Visual Studio 2012. If not, disregard this answer. Visual Studio 2012 typedef‘s high_resolution_clock to system_clock. Sadly, this means it has crappy precision (around 1 ms). I wrote a better high-resolution clock which uses QueryPerformanceCounter for use in Visual Studio 2012…

HighResClock.h:

    struct HighResClock
    {
        typedef long long                              rep;
        typedef std::nano                              period;
        typedef std::chrono::duration<rep, period>     duration;
        typedef std::chrono::time_point<HighResClock>  time_point;
        static const bool is_steady = true;

        static time_point now();
    };

HighResClock.cpp:

namespace
{
    const long long g_Frequency = []() -> long long
    {
        LARGE_INTEGER frequency;
        QueryPerformanceFrequency(&frequency);
        return frequency.QuadPart;
    }();
}

HighResClock::time_point HighResClock::now()
{
    LARGE_INTEGER count;
    QueryPerformanceCounter(&count);
    return time_point(duration(count.QuadPart * static_cast<rep>(period::den) / g_Frequency));
}

(I left out an assert and #ifs to see if it’s being compiled on Visual Studio 2012 from the above code.)

You can use this clock anywhere and in the same way as standard clocks.

More Related Contents:

  1. Why does this C++ snippet compile (non-void function does not return a value) [duplicate]
  2. What are the uses of std::chrono::high_resolution_clock?
  3. Extract year/month/day etc. from std::chrono::time_point in C++
  4. How to convert std::chrono::time_point to calendar datetime string with fractional seconds?
  5. Outputting Date and Time in C++ using std::chrono
  6. error C2679: binary ‘
  7. std::put_time implementation status in GCC?
  8. Initializer list not working with vector in Visual Studio 2012? [duplicate]
  9. C++ Add months to chrono::system_clock::time_point
  10. Difference between std::system_clock and std::steady_clock?
  11. Is it valid to bind non-const lvalue-references to rvalues in C++ 11?(modified)
  12. How to enforce the ‘override’ keyword?
  13. Implementing comparison operators via ‘tuple’ and ‘tie’, a good idea?
  14. Create N-element constexpr array in C++11
  15. Why does passing object reference arguments to thread function fails to compile?
  16. C++11 thread-safe queue
  17. const& , & and && specifiers for member functions in C++
  18. Why doesn’t SFINAE (enable_if) work for member functions of a class template?
  19. Error: variable “cannot be implicitly captured because no default capture mode has been specified”
  20. copy elision: move constructor not called when using ternary expression in return statement?
  21. Why can’t I create a vector of lambdas (of the same type) in C++11?
  22. Why there is no placement delete expression in C++?
  23. When do extra parentheses have an effect, other than on operator precedence?
  24. C++11 rvalue reference calling copy constructor too
  25. Conflict between copy constructor and forwarding constructor
  26. C++11: Replace all non-owning raw pointers with std::shared_ptr()?
  27. templated typedef?
  28. Visual Studio 2013: CL.exe exited with code -1073741515
  29. “What happened to my SFINAE” redux: conditional template class members?
  30. Concatenate compile-time strings in a template at compile time?

Leave a Comment