On Tue, 25 Jan 2005 19:30:04 +0100, you wrote:
I'm quite certain that many programs use that function for extremely time critical code (games, anyone??), and that thus the Windows function is equally highly optimized, certainly much less slow than a gettimeofday() call.
This should remain based on rdtsc IMHO, or on equally suitable and fast methods (ACPI counter, ...).
On my Windows machine (win2K) the calling sequence is kernel32->ntdll->hal. In other words a switch to kernel mode with associated overhead, similar to gettimeofday. I believe a program that would be critically depending on this will use the rdtsc instruction directly.
Why do you believe otherwise?
Or did you actually test it with programs calling it a large number of times, or test its performance behaviour on Windows
I did not. On Linux gettimeofday() is fast enough to match the resolution of the timer, approx. 1usec.
Rein.