[time-nuts] sync computer clock ticks

[M. Warner Losh]

In message: <25630a120801040918x2203daebs7eb0de5f00ffc56c at mail.gmail.com>
            "michael taylor" <mctylr at gmail.com> writes:
: On Jan 4, 2008 12:03 PM, M. Warner Losh <imp at bsdimp.com> wrote:
: >
: > I don't know about other people, but out of the box I get sub 20ms
: > synchronization.  Right now, it is sitting at about 12.5ms:
: >
: >      remote           refid      st t when poll reach   delay   offset  jitter
: > ==============================================================================
: > *xxxxx.yyyyyy.co 10.7.1.1         2 u  965 1024  377   64.176  -12.570   0.508
: >
: 
: That's a 12 ms offset from UTC, as far as I understand the original
: poster only needs  <= 1 microsecond synchronization on his local
: network.

I have no experience with gige networks, but the best I've been able
to do on 100baseT networks is 50us.  I'm unsure what <1us
synchronization really means, since that's starting to get below the
level of system calls on fast machines.

Warner