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.
