Clock delay

[Stewart Nelson]

> - The clock has delays just with 2.6.8-1.521 kernel (not with Win2000 or
> another kernel). The biggest delay it has is around 10 minutes, and it
> takes this delay progressively during the first two hours. Afterward, no
> more delay.

> If you won't be using NTP, check the BIOS time before booting,
> the system time right after it starts up, the system time just
> before shutdown, and the BIOS time after shutdown.  That should
> show whether the time is being lost at startup, during operation,
> or at shutdown.

> Right after it starts up, the system time matches the BIOS time. Just
> before shutdown, it has a delay, as I said like 10 min. as maximum, just
> the same as the BIOS time, so the time is lost during operation, which
> is logical as it doesn't happen with Win2000.

My system does not accumulate such a delay, even when not connected
to the network.

Sorry, it's beyond my expertise to say what might be wrong.
I would guess that you are losing timer interrupts, because of
higher priority interrupts, or a process that is disabling them.
Perhaps you can get a clue from interrupt counts or process run times.
You could try running adjtimex in --compare mode to see if time gets
lost gradually or in bursts.

If whatever is wrong does not adversely affect operation,
there are various workarounds:

Simplest would be to comment out the call to hwclock in
the 'halt' script.  Your time would still be off by as much
as 10 minutes, but it wouldn't accumulate, or mess up Windows.

You could also start up adjtimex in --adjust mode, which
should keep your system time pretty much in sync with the
hardware clock.  You wouldn't be able to set the system
clock from the Net (maybe unimportant if you do that from
Windows), or you could have a script that runs hwclock to
set the hardware clock from network time.

--Stewart