On 15 October 2013 13:48, Felipe Farinon <felipe.fari...@powersyslab.com>wrote:
> I have found that > VirtualBox's QueryPerformanceCounter doesn't guarantee monotonicity > https://www.virtualbox.org/ticket/11951. They argue that even Windows > QueryPerformanceCounter doesn't guarantee it. > This is true, the performance counters are highly unreliable. With OpenPGM I followed the SQL Server teams approach and move towards Windows multimedia timers they offer greater stability and lower cost. Copy & pasting: /* Multi-media like timer API, returns 100-nanoseconds intervals. * * Faster than QueryPerformanceCounter and hence deployed for SQL Server. * http://blogs.msdn.com/b/psssql/archive/2008/12/16/how-it-works-sql-server-no-longer-uses-rdtsc-for-timings-in-sql-2008-and-sql-2005-service-pack-3-sp3.aspx */ static pgm_time_t pgm_mmtime_update (void) { FILETIME ft; int64_t aligned_ft; GetSystemTimeAsFileTime (&ft); memcpy (&aligned_ft, &ft, sizeof (int64_t)); return (pgm_time_t)( aligned_ft / 10 ); } The caveat being you are still affected by NTP adjustments, but this is available on platform where *GetTickCount64* is not. GHC Haskell had similar discussions: http://ghc.haskell.org/trac/ghc/ticket/5865 Chromiums discussion on topic: https://chromium.googlesource.com/chromium/src/+/acca91d2f89419fe27e275e55fac228713497da4/base/time_win.cc -- Steve-o
_______________________________________________ zeromq-dev mailing list zeromq-dev@lists.zeromq.org http://lists.zeromq.org/mailman/listinfo/zeromq-dev
