[ntp:questions] Time reset

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Fri Apr 4 16:59:46 UTC 2008


>My current problem is that drift settles at 82ppm (what I called <90 in
>previous email) in one run and then 32ppm in another run (with a reboot
>between).  This is similar to the problem I had with stepping disabled
>where drift would go from +500ppm in one run and then swing all the way
>to -500ppm in another run (usually with a reboot between).  I am not
>going to spend another minute troubleshooting this problem until we get
>an updated linux kernel.  I will dig into it more deeply if the new
>kernel exhibits this same drift instability.

I think we are talking about two different bugs here.

The different drifts on reboot are due to a quirk in the tsc
calibration code in the kernal.  Grep your sys log for messages
like these:
  Mar 30 21:56:23 shuksan kernel: Detected 2793.091 MHz processor.
  Mar 30 22:23:28 shuksan kernel: Detected 2793.067 MHz processor.
  Mar 30 22:42:31 shuksan kernel: Detected 2793.037 MHz processor.
  Mar 30 23:03:21 shuksan kernel: Detected 2793.085 MHz processor.
  Mar 31 00:07:37 shuksan kernel: Detected 2793.147 MHz processor.
Those bottom bits jumping arround correspond to the different
drift values.

If you only have one system, you can pick one and hack your
kernel to smash in a constant value at the right place.

Or you can add something like this to your boot line:
  clocksource=acpi_pm
That's assuming your hardware has acpi and whatever.

I've been using it for a while.  I haven't noticed any quirks,
but who knows.

-- 
These are my opinions, not necessarily my employer's.  I hate spam.




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