exakte Zeitmessungen auf Multiprozessoren

[hathor]

Enhanced Timer
This Enhanced Timer (Etimer) is based on two Windows* API functions; QueryPerformanceCounter and QueryPerformanceFrequency. There is no way to know which frequency Microsoft is using to implement those two functions on any given platform. But one thing for sure is that the frequency of that timer will never change during the course of timing. The timer can be either the chipset timer or the power management timer or something else.

http://www.delphi-forum.de/viewtopic...=528456#528456

http://www.delphi-forum.de/viewtopic...=528819#528819

With Multi-threaded Applications in Multi-Processor Systems

The Etimer can also be used in Multi-processor systems. Since the time retrieved from the timer will be slightly different on different processors it is important that the start and stop time be taken on the same processor to ensure accuracy. The Etimer was developed to deal with multi processors. It first searches for the available processors and uses the first one available. The processor ID of the processor is used to take the initial reading and is stored in the Etime_t variable so that the final reading will be measured on the same processor. If no processor is available or the processor where the start time was taken is not available, the Etime function will return an error code.

http://software.intel.com/en-us/arti...nhanced-timer/