On Thu, Nov 20, 2003 at 05:56:19PM +1100, Ronnie Sahlberg wrote: > I think some versions of windows only provide 10ms or something like that > accuracy. > some versions of linux can provide sub ms accuracy depending on the CPU and > how the kernel was compiled.
Note also the difference between "precision" and "accuracy". An OS might have a very high-resolution clock, providing high-precision time stamps. However, packets aren't time-stamped the instant the first octet, or the last octet, is processed by the network adapter (unless the adapter does the time stamping). Instead, they're time-stamped by something in the OS code path between the point at which the host sees the packet (which might be after the last octet is processed by the adapter, due to interrupt latency, polling rather than per-packet interrupting in order to batch packet arrival, etc.) and the point at which it's delivered to the packet capture mechanism.
