[Xen-devel] Re: [Xen-users] ntpd under Xen Dom0 exhibits extremely high jitter/noise? runs stable/quiet under non-xen kernel.

[mail ignored <0.bugs.only.0@xxxxxxxxx>]

On Sun, Jan 17, 2010 at 1:33 PM, Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote:
> Tbh I don't think we've ever done a detailed
> analysis of ntp performance on Xen before -- this is something we might be
> able to improve.

just fyi -- this may be all old info for you -- this

 "Kernel Model for Precision Timekeeping"
  http://www.eecis.udel.edu/~mills/ntp/html/kern.html

and the site/info around it, seem to be the authoritative resource on
timekeeping with ntp (function, debugging, etc).

it's been a great resource in understanding the expected behavior of ntp.

i also found good general guidance in

 "Network Time Protocol (NTP) Overview and Configuration: An Internet2 Cookbook"
  http://e2epi.internet2.edu/npw/binder-docs/ntp-cookbook.pdf

although it does include a # of quotes/references to Mills' bias
against Linux, e.g.,

  “I have confronted Linux many, many times with broken this and that
and concluded I will not attempt to examine, fix, or judge anything
Linux. You are on your own.” —David L. Mills, 2004-10-20

so it's not clear, at least to me, if there are in fact 'deeper'
issues with ntp at hand.  hopefully that's gotten better over the
years ...

hth.

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