Consider an idle Linux 2.6.20-rt8 system, equipped with a single PCI-E
gigabit Ethernet NIC, running on a modern CPU (e.g. Core 2 Duo E6700).
All this system does is time stamp 1000 packets per second.
Are you claiming that this platform *cannot* handle most packets within
less than 1 microsecond of their arrival?
Yes I claim it. You expect too much of this platform, unless "most" means
10 % for you ;)
If you replace "1 us" by "50 us", then yes, it probably can do it, if "most" means 99%, (not 99.999 %)
Anyway, if you want to play, you can apply this patch on top of linux-2.6.21-rc2 (nanosecond resolution infrastructure needs 2.6.21)
I let you do the adjustments for rt kernel.
This patch converts sk_buff timestamp to use new nanosecond infra
(added in 2.6.21)