On Fri, 11 Feb 2005 19:30:36 -0500, christopher diggins wrote: [...] std::clock() and I assume QueryPerformanceCounter() give you an amount of clock ticks. This number is only incremented when the CPU works on your task.
AFAIK your assumption is wrong.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui... watch the line wrap. QueryPerformanceCounter uses the CPU clock and is not per task but system wide.
Can you point me to documentation which supports your assertion?
The only problem with QueryPerformanceCounter() is that it can "jump" on some chipsets.
I believe this problem is perhaps not restricted to QueryPerformanceCounter() but to any counter counting mechanism, as the problem is at the chipset level not the API level.
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 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. This bit me on commercial code and I resorted to timeBeginPeriod(1); timeGetTime(); instead with no issues. Martin