Greg Stark <gsstark(at)mit(dot)edu> writes:
> There seem to be two types of overhead going on. There's the amount of time
> spent in gettimeofday itself which is pretty consistent.
That is a fact not in evidence. The impression I had from that
linux-kernel discussion was that the problematic kernel code was looping
until it got consistent results from successive hardware reads. I'm
not at all sure that you can make the above assertion across all
varieties of clock hardware, or even all common varieties.
regards, tom lane