dlang: actually, all the work that has gone into making timestamping fast in the last decade seems to have paid off. Eric Dumazet proved to me that it is now incredibly cheap, and I think pursuing "time in queue" has great potential to get us into the sub 30ms range for inherent latencies across a wide range of gear.
I knew in my gut, too, that timestamping was expensive. It *was* - in the early 00s. My gut was wrong.