No, there is a very particualar problem relating to QueryPerformanceCounter() on some (old?) chipsets the can cause it go backwards in time and wrap after approximately 20 minutes. I reported
At 07:30 PM 2/13/2005, christopher diggins wrote: this
to microsoft some years ago and it was confirmed an issue. (at the time
only happened to me on one particualar celeron / motherboard configuration). By backwards in time I mean you could call the counter in
a loop and have a reported time earlier than one got the previous iteration.
Really? That is different than the issue documentation I found at http://support.microsoft.com/default.aspx?scid=kb;EN-US;q274323 which stats that the QueryPerformanceCounter() can jump *ahead* a few seconds. I wonder if the status of the issue has changed to this new version or the documentation just sux.
There is another problem with QueryPerformanceCounter(); the latency (time spent executing the call itself) varies dramatically depending on (1) the version on Windows, and (2) which compiler was used. Why the compiler should have a strong effect on the latency of an API call is a mystery. John Maddock and I ran some tests several years ago, and both of us could reproduce the effects. I recently downloaded some timing code written by someone else, tried it with several compilers and the effect still appears to exist with current compilers. So be careful, and be sure to test with different versions of Windows and different compilers. --Beman