Re: Accurate time measurement

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"Paul MH" <paulmorrishill@xxxxxxxxxxxxxx> wrote in message
news:1177782440.185915.145290@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

thanks for replys ive found some information about
different accuricies
http://support.microsoft.com/kb/172338

I've just had a quick look at that Microsoft link and it explains away the
10 millisecond (on their own test machine) resolution of GetTickCount and
timeGetTime by saying, "Multiple statements execute before either
GetTickCount or timeGetTime record a change" and adding, "The actual number
of loops will vary depending on the background tasks the operating system is
executing". I find that statement at best totally misleading and at worst
completely untrue, at least as an explanation as to why it takes 10
milliseconds between "ticks". In actual fact the "reading" of the
appropriate counter by GetTickCount and by timeGetTime is actually very much
faster than the reading of the appropriate counter by
QueryPerformanceCounter. And they make no mention of the fact that you can
increase the resolution of both GetTickCount and timeGetTime using
timeBeginPeriod. Odd that :-)

Mike








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