"Terje Mathisen" <> wrote in message news:[email protected]...
[]
Have you tried to time the minimum clock reading time with RDTSC or
GetPerformance* counter calls?
I wrote a tiny test program on my Win7-64 laptop, it got:
Reading the system clock 10000000 times, minimum reading time = 24 clock
cycles,
minimum OS step = 0 ticks, maximum OS step = 10000 ticks
The clock frequency is 2.7 GHz or so, the FileTime ticks should be 100
ns each, so my OS clock is making 1 ms steps, while the clock reading
time is down to less than 10 ns!
[]
Terje
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"
I wrote a similar test program some time back, and it's available for
download here:
http://www.satsignal.eu/software/net.htm#PCClockTiming
You can see from the screen-shot that QueryPerformanceCounter took ~200 ns
on an older XP system with an Intel processor, and ~2 us on a Vista PC
with an AMD processor. I didn't time GetSystemTimeAsFileTime, but I could
add that if it's needed.
Cheers,
David
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