[sllug-members]: SLES clock drift

[Scott K]

On 9/5/07, Matthew Hatch <matthew at azza.com> wrote:
>
> I've run unto this problem using an Athlon X2, as well as my laptop
> (Pentium M).  I've found the cause on these two machines to be the CPU's
> PowerNOW or Speedstep stuff changing my CPU clock speed.  If you change
> your cpufreq scaling governor to performance ("echo performance >
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor" or some such),
> the clock skew is less noticeable in my experience.
>

I can think of only one reason to mess with this setting. If you had an
intensive process to run on your laptop, and didn't care if you burned
through your battery faster. There's generally no reason to run your
processor harder and hotter than it feels like it needs to. Generally
speedstep(etc.) only kicks in when you aren't doing much or you're running
on battery power. No reason to keep your server running hot all the time
with increased fan noise (and external cooling requirements) while wasting
power.

The PIT timer method tells your guest OS not to over correct timing and
might remove all your time problems. If it loses time because of missed
interrupts, the *clock=pmtmr* option might also be worth looking at.

Is it a crime if I post the most informative relevant quick Google on this
problem? http://support.microsoft.com/kb/918461 (ignore the source of that
link)
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