[ofw][patch][WinVerbs tests] Re: fix IPv6 related connection problem

[Fab Tillier]

> The timestamp has been moved to after
> post, because on Win2k8 it takes 1.1 us !!! And this is what doubles the
> latency!

You can use the __rdtsc intrinsic, it has far lower overhead.

Depending on the system, QueryPerformanceCounter will go to the system PM timer, which can involve a good amount of overhead.

> We placed it after post, where the test anyway does nothing...
> BTW, the same test with timestamps on your favorite place :) on win2k3
> takes 1.1 usec less, timestamping there takes several nanos.

Yes, probably a difference in the HAL that changes the timer source.

> Another solution would have been a proprietory function, that performs
> timestamping on win2k8 fast.

#pragma intrinsic(__rdtsc)

start = __rdtsc();