Silex wrote:
I did some tests with the current boost::posix_time::microsec_clock and it *looks* like GetSystemTimeAsFileTime() has low level resolution,
The resolution is good, but the time isn't updated any more often than the system clock (usually some 10-15 milliseconds).
BUT I read somewhere that it's overhead is huge compared to QueryPerformanceCounter.
I'd say it's usually the opposite way around, unless somethings changed due to some later WinXP service pack or hot fix. QPC can be a real performance killer on single CPU systems. It's been a while since I tested thought, so I can't speak for certain for how the performance counter is implemented on HT and/or dual-core platforms.
I'll try to see if there's a way to get the epoch from QueryPerformanceCounter or timeGetTime, so I could make a usable microsec_clock based on it.
Are you really talking about getting an absolute time with milli-/microsecond resolution? Be prepare to put down some work - there's no supported way of getting a correlation between the monotonic counters and calendar time. // Johan