Flaky timekeeping?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

Okay, I've got a slab running, now.  But the first thing I did, as
always, is to rebuild stuff.

And the clock is drifting, and, worse, drifting irregularly.

I started ntpd as a broadcast client (I have another machine in the
broadcast domain broadcasting time).  Here's what I get querying it
every 64 seconds from another machine:

     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64    3 0.00781  0.509586 1.98584
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64    7 0.00781  1.322884 1.39456
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64   17 0.00781  1.640805 0.97235
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64   37 0.00781  1.955022 0.66771
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64   77 0.00781  1.777081 0.44275
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64  177 0.00781  2.075839 0.26672
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64  377 0.00781  2.888184 0.09338
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64  377 0.00781  3.205274 0.09331
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64  377 0.00781  3.034869 0.09335
     remote           local      st poll reach  delay   offset    disp
=======================================================================
 10.0.1.1        10.0.1.4         4   64  377 0.00781  3.854038 0.09341

This looks bizarre to me.  Does next68k suffer from the same problem as
mac68k wherein clock interrupts are of a low enough hardware priority
that they aren't reliable?  Or is there something stranger going on?

In case it matters, this is with 4.0.1.  I was tempted to run 1.4T, and
may end up having to fall back to that, but I'd _like_ SCSI support,
and 4.0.1 is the earliest of the versions I run elsewhere (and thus am
set up to deal with easily) that supports SCSI on this hardware.
(Given how sluggish compiles are being, and my experiences with 4.0.1
on x86 machines with as little RAM as this slab has (32M), I fear I may
have to fall back to 1.4T just in order to keep it from thrashing
itself to death trying to build the world.  I'm hoping the 68k compiler
isn't as much of a pig as the x86 compiler is.)

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