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Date: Tue, 8 Apr 2014 22:02:29 +0700
From: Alexey Dokuchaev <danfe@nsu.ru>
To: John Baldwin <jhb@freebsd.org>
Subject: Re: System clock falls behind quickly on Mac mini G4
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On Tue, Apr 08, 2014 at 10:41:44AM -0400, John Baldwin wrote:
> It wouldn't be tsc_freq on a powerpc box.  You'd need to see what your
> timecounter is and what frequency it is using (kern.timecounter nodes)
> and see if that is adjustable.

Yup, sorry; I forgot that our TSC maps to actual x86 Time Stamp Counter,
not being some aggregated MI relatively high-precision time keeping thing.

Does not look I can do much about it though:

  $ sysctl kern.timecounter
  kern.timecounter.fast_gettime: 1
  kern.timecounter.tick: 2
  kern.timecounter.choice: timebase(0) dummy(-1000000)
  kern.timecounter.hardware: timebase
  kern.timecounter.alloweddeviation: 5
  kern.timecounter.stepwarnings: 0
  kern.timecounter.tc.timebase.mask: 4294967295
  kern.timecounter.tc.timebase.counter: 3224483187
  kern.timecounter.tc.timebase.frequency: 41620907
  kern.timecounter.tc.timebase.quality: 0

./danfe