3 ms·

This really looks like a problem with the Windows implementation of std::chrono::steady_clock more than anything else. This clock is nano-second resolution on m

This really looks like a problem with the Windows implementation of std::chrono::steady_clock more than anything else. This clock is nano-second resolution on most *nix platforms (incl. Mac OS X) and offers the strictly increasing guarantee required (without possibility of discontinuities). It seems like (in the long term) it would be better to push some std::chrono::steady_clock Windows patches to stdlibc++/libc++/MSVC and use this instead of re-inventing the wheel.

stinos 12y ago
Spot on: http://connect.microsoft.com/VisualStudio/feedback/details/753115/ http://connect.microsoft.com/VisualStudio/feedback/details/7... and https://connect.microsoft.com/VisualStudio/feedback/details/719443/ https://connect.microsoft.com/VisualStudio/feedback/details/..., and the last response: Hi, Thanks for reporting this bug. We've fixed it, and the fix will be available in the next major version of VC (i.e. after 2013). steady_clock and high_resolution_clock are now synonyms powered by QueryPerformanceCounter() converted to nanoseconds. QPC meets the Standard's requirements for steadiness/monotonicity. Additionally, the CRT's clock() has been reimplemented with QPC. While this improves precision and conformance to the C Standard (as QPC is monotonic), we are aware that this is not completely conformant. Our CRT maintainer has chosen to avoid having clock() return CPU time advancing faster than 1 second per physical second, which could silently break programs depending on the previous behavior. So it is expected that VS2014 should have the fixes. On a sidenote, I've seen most of the code, if not all, posted by the OP already before while searching for the same functionality (eg the piece after "you will write your own function:" is followed by something that to me seems like a straight up copy from some FOSS project, even the comments seems to match - ok I cannot be 100% certain on this but if it's the case it would be nice to mention the source). I can't find it atm, but I am sure a C++11 clock compatible implementation using QPC has been posted on StackOverflow.

stinos 12y ago

Spot on: http://connect.microsoft.com/VisualStudio/feedback/details/753115/ http://connect.microsoft.com/VisualStudio/feedback/details/7... and https://connect.microsoft.com/VisualStudio/feedback/details/719443/ https://connect.microsoft.com/VisualStudio/feedback/details/..., and the last response: Hi, Thanks for reporting this bug. We've fixed it, and the fix will be available in the next major version of VC (i.e. after 2013). steady_clock and high_resolution_clock are now synonyms powered by QueryPerformanceCounter() converted to nanoseconds. QPC meets the Standard's requirements for steadiness/monotonicity. Additionally, the CRT's clock() has been reimplemented with QPC. While this improves precision and conformance to the C Standard (as QPC is monotonic), we are aware that this is not completely conformant. Our CRT maintainer has chosen to avoid having clock() return CPU time advancing faster than 1 second per physical second, which could silently break programs depending on the previous behavior. So it is expected that VS2014 should have the fixes. On a sidenote, I've seen most of the code, if not all, posted by the OP already before while searching for the same functionality (eg the piece after "you will write your own function:" is followed by something that to me seems like a straight up copy from some FOSS project, even the comments seems to match - ok I cannot be 100% certain on this but if it's the case it would be nice to mention the source). I can't find it atm, but I am sure a C++11 clock compatible implementation using QPC has been posted on StackOverflow.